Find out what was shared
If the wrong group received a visitor sheet, disable access where possible, tell that group which file was sent in error, and send a corrected sheet to the intended people. Review whether any exposed access code needs to be changed separately. Distinguish erasing a link from a message, turning off access at the source and removing a particular person's permission. The first action alone leaves a copied address usable.
Test at the source
Open the document’s sharing controls. Check direct invitations, access granted through a group and any “anyone with the link” setting. Remove or narrow the relevant grant, then verify with an authorized test session outside your account. Testing from the owner's signed-in browser can misleadingly show that everything still opens.
Contact people who received a copy
If the document contained personal information or an access detail, tell the intended owner what was shared. Ask the unintended recipients to remove their copies. Replace any exposed active code when appropriate. Record which steps were confirmed and which depend on a recipient’s response.