By default, your spreadsheet is visible only to you. Even if other accounts manage to get the link to your spreadsheet, they will encounter the following page:
Unless the user has the sufficient hacking skills needed to circumvent the access controls by Google, your data is safe in its place and the user has to request access.
In this tutorial, you will learn how to control the level of access for authorized users.
Add users to view your spreadsheet and control their access level
Step 1: Click the Share button on the upper-right corner of Google Sheets.
The Share with people and groups will be loaded.
Step 2: You have options to add users to view the sheet or to make it public.
Option 1: To make it public, simply click the Change to anyone with the link on the lower portion of the box. This will appear after clicking it:
You can also control the access level to the public by clicking the drop-down box Viewer on the right side of the box.
To revert back the access to the spreadsheet to private, click Anyone with the link and select Restricted on the appearing drop-down box.
Option 2: To add a selected list of users, type or paste the list of their Gmail email accounts on the box labeled Add people and groups.
Once you’ve added the list, the box will change to the following format:
You can set their permissions to simply viewing the contents as a Viewer, adding comments as a Commenter, and outright editing the contents as Editor. You can add a custom message in the message box as this is sent in an email. Click Send once you are done.
Protect certain sheets of a spreadsheet
There are cases where you want to allow editing privileges to certain sheets but protect other sheets from changes. Here are the steps:
Step 1: Look for the tab of the sheet on the lower portion of the screen, and click the arrow besides the sheet name.
Step 2: A list of options will appear after clicking the arrow. Click Protect sheet.
Step 3: A sidebar labeled Protected sheets & ranges will appear on the right side of Google Sheets.
Select the sheet name on the drop-down list and then click Set permissions.
Step 4: A pop-up box will appear containing the options for the permissions.
Click the drop-down box to select the options:
The Only you option restricts editing to you, who is the owner of the sheet. Selecting Custom means you can add other users as Editor of that sheet while others who can access it would remain as Viewers or Commenters. A box will appear where you can add the Gmail addresses of the selected users.
Step 5: Click Done.
You can use the same steps to protect certain ranges instead of certain sheets. At Step 3, click the Range tab in the sidebar instead of the Sheet tab, and then specify the range.
Clicking Set permissions will bring you to the same pop-up box with the same options as in Step 4.