You’ll already be aware that you can share documents, spreadsheets, presentations and drawings with your colleagues, and that you can also specify the access level for these collaborators, i.e. you can grant them full editing privileges, or just the ability to view a file or to add comments.
When you do so, your colleague will by default receive a notification. Here’s an example from an email notification:
Google has made a small improvement to the sharing system. Now, when you’re invited only to view a document, a blue button appears in the document toolbar:
Clicking the button to open the message (as I’ve done in the image above) confirms your current share status, and offers you a link via which you can contact the document owner to request full access. A similar button appears if you are allowed to comment on the document, but this time it’s green:
In either case, clicking on the REQUEST EDIT ACCESS link opens a dialog via which you can send your request to the document’s owner, optionally including a personal message in which you can make your case for having edit permissions:
The option does not show for docs shared on the web, or with Anyone with a link permissions.