fill in

To fill; to replace material that is absent or has been removed.

“After you're done laying the pipe, fill in the trench.”

To inform somebody, especially to supply someone missing or missed information.

“If you know anything about this, maybe you can fill me in.”

To substitute for somebody or something.

“He can't go on vacation very often because there is nobody to fill in for him.”

To complete a form or questionnaire with requested information.

To beat up; to physically assault.

“Talk to me like that again and I'll fill you in!”