By the end of this lesson you will be able to
- Decide whether to send a file as an attachment or as a sharing link.
- Explain the difference between view, comment and edit permissions.
- Name files and organise a shared folder so that others can find things.
- Check a file for sensitive information before sharing it.
Sending a file seems simple until the email bounces for being too large, a colleague edits the wrong copy or a private document ends up visible to everyone. Sharing is a skill with two parts: choosing the right method and setting the right permissions. This lesson gives you a way to decide, and the habits that keep your work clear and safe.
Attachment or link?
An attachment is a file that travels inside an email message. The recipient gets their own copy. A sharing link is a web address that points to a file stored online, in cloud storage. The recipient opens the one original, and you decide what they may do with it.
Attachments are simple and work for everyone, but they have two weaknesses. Email providers limit the size of a message, often at around 20 to 25 megabytes in total. Attached files are also slightly larger than they are on your disk, because email has to convert them to text, so a file close to the limit may be refused. Second, every copy is separate. If you send a draft to five people and then change it, five old copies are still out there.
| Attachment | Sharing link | |
|---|---|---|
| Size | Limited, commonly 20 to 25 MB per message (check your provider) | Much larger files are possible, within your storage allowance |
| Copies | Each person gets a separate copy | One original that everyone opens |
| Changes | You must send again | Everyone sees the latest version |
| Control | None once sent | You can change or remove access later |
| Needs the internet to open | No, once downloaded | Yes, usually |
| Best for | Small, final files such as a signed letter or a CV | Large files, drafts, and files several people work on |
- Is the file under about 10 MB?
- YesDo thisSend it as an attachment.
- NoWill people edit it together, or need to see later changes?
- YesDo thisUse a sharing link with edit permission.
- NoCould you shrink it by zipping or exporting a smaller version?
- YesDo thisZip or export, then attach if it fits.
- NoDo thisUse a sharing link with view permission.
Read this figure as text
A yes or no decision tree that leads to an attachment, a zipped attachment or a sharing link.
A decision tree. First question: is the file under about 10 megabytes? If yes, send it as an attachment. If no, second question: will people need to edit it together or see later changes? If yes, use a sharing link with edit permission. If no, third question: could you shrink it by zipping or exporting a smaller version? If yes, zip it and attach it if it is then small enough. If no, use a sharing link with view permission.
Permissions: who can do what
When you share a link, you choose two things: who can use it and what they can do. These choices are the access levels of the file. Most services offer these:
- Viewer (view only): can read and download, but cannot change your file. This is the safe default.
- Commenter: can read and add comments, but cannot change the text itself.
- Editor: can change the content, and often can share it onwards. Give this only to people who really need it.
The second choice is who. 'Specific people' means only the email addresses you enter can open the file, and they usually have to sign in. 'Anyone with the link' means that anybody who gets the address can open it, even if you did not mean them to, because links get forwarded, copied and sometimes guessed. For anything personal, choose specific people.
- Marker 1: The owner controls sharing
- Marker 2: Editor: can change the file
- Marker 3: Viewer: can only read it
- Marker 4: Restricted is safer than Anyone with the link
Read this figure as text
A simulated sharing dialogue with a list of people and access levels, and a general access choice for the link.
A dialogue titled Share Budget-2026. It lists three fictional people with their access: Amina is the Owner (marker 1), Joseph is an Editor (marker 2) and Wanjiru is a Viewer (marker 3). Below, the General access line says Restricted: only people listed can open (marker 4). Buttons at the bottom read Copy link and Done. Restricted is safer than Anyone with the link.
Names and folders that work for other people
When a file leaves your computer, your private habits do not go with it. The person who receives final2.docx cannot tell what it is. A good shared name says what the file is, who it is from and which version it is: Budget-2026-v2-Amina.xlsx. Put the date first if the order matters: 2026-03-14-minutes.docx. Avoid spaces and special characters if the file will be shared by link, since they can make web addresses awkward.
The same goes for folders. A shared folder is a small office, and a clear structure stops people asking where things are. Use a few folders with clear names, put the oldest work in an Archive folder and keep one place for the current version.
- Community-Garden-2026
- 01-Plans
- Garden-plan-v3.docxCurrent version
- 02-Budget
- Budget-2026-v2.xlsx
- 03-PhotosPhotographs from site visits
- 99-ArchiveOld versions live here
- Garden-plan-v1.docx
Read this figure as text
A folder tree for a shared project with a drafts folder, a final folder and an archive folder.
A tree. The top folder is Community-Garden-2026. It holds four items: 01-Plans, containing Garden-plan-v3.docx; 02-Budget, containing Budget-2026-v2.xlsx; 03-Photos, a folder of photographs; and 99-Archive, which holds old versions such as Garden-plan-v1.docx. Numbers at the front of the folder names keep them in a sensible order, and the Archive folder keeps old versions out of the way.
Sensitive data: think before you share
Sharing is permanent in practice. Once someone has a copy, you cannot take it back. Before you share, ask what is actually in the file. Documents often contain more than the part you meant to share: a spreadsheet with hidden columns, a CV with a home address, a photo that shows a house number. Do not share identity numbers, bank details, passwords, medical information or other people's personal details unless there is a clear need and the recipient is someone you trust.
- Check the recipient. Is the email address spelled correctly? A near-miss address sends your file to a stranger.
- Share the minimum. Send one page, not the whole file, if only one page is needed.
- Choose view only unless the person must edit.
- Send secrets separately. If a file is protected by a password, give the password by another route, such as a phone call.
- Clean up later. When a project is over, remove people from the sharing list and delete public links.
Common mistakes
✖ Instead of: Sending a large file by email as three separate attachments.
✔ Do this: Check the combined size. Use a sharing link or zip and shrink the files.
✖ Instead of: Giving Editor permission to everyone because it is easier.
✔ Do this: Start with Viewer and give Editor only to people who must change the file.
✖ Instead of: Sending a document with a password in the same email as the file.
✔ Do this: Send the password by another route, such as a call, so that one stolen message is not enough.
If something goes wrong
- My email was rejected because the attachment is too large.
- Check the file size in its properties. Zip it, or save a smaller version (for photos, reduce the picture size). If it is still too large, upload it to cloud storage and send a link.
- A person says they cannot open my link.
- Check the permission: the link may be set to specific people and they signed in with another email address. Share with the exact address they use, or ask which account they are using.
- I am told 'You need permission' when I open a link.
- You may be signed in with the wrong account. Switch accounts, or use the Request access button and wait for the owner to approve.
Key terms
- attachment
- An attachment is a file sent along with an email message.
- Sharing link
- A web address that lets other people open a file you have stored online.
- Access level
- The kind of access a person is given to something you share, such as only viewing it or being allowed to edit it.
- Cloud storage
- Online space where a company keeps your files so you can reach them from any device.
Practise it for real
Reading is not the same as being able to do it. Complete these on your own computer, then tick only what you have actually done. These ticks are your own honest record: nothing checks them for you.
Choose the method for five files
For each of these files, decide whether you would use an attachment, a zipped attachment or a sharing link, and with what permission: (1) a one-page CV of 80 KB for a job application; (2) a 150 MB video of a family event for ten relatives; (3) a budget spreadsheet three volunteers edit together; (4) 200 photographs of 3 MB each; (5) a scan of your national identity card. Write one reason for each choice.
Challenge: design a shared folder and names
Imagine you and two friends are organising a school fundraising event. On paper or in a practice folder on your laptop, design a shared folder with at least three sub-folders and an Archive folder. Write five file names that follow a clear pattern, including version numbers or dates, and decide who gets view and who gets edit access.
Knowledge check
6 questions. You need 80% to pass. Mistakes here are part of learning, and you can retry as often as you like.
Summary
- Attachments suit small, final files; sharing links suit large files and shared work.
- Give people the lowest access level that does the job: viewer, then commenter, then editor.
- Anyone with the link means anyone, so use specific people for private files.
- Clear file names and folders save everyone time.
- Check what a file contains and who is receiving it before you share.
Checklist: can you do these?
Marking a lesson as read does not prove you can do it. Skills count as demonstrated when you pass the quiz (not yet) and complete the practical tasks (not yet).
Related lessons
References and further reading
Official sources for details that can change between versions.