What is an access request?

When you open a Drive link you have no access to, you are not simply refused — you can ask, and the request goes to whoever owns the folder.

They approve it, which gives you edit access, or deny it, optionally with a reason so you know whether to ask again or ask somebody else.

It exists because the alternative is worse. Without it, being left off a share turns into a message, a wait, and a guess about who to chase — for something the owner can settle in one click.