in
1.
( BrE ) to complete a form, etc. by writing information on it :
to fill in an application form
To order, fill in the coupon on p 54.
2.
to fill sth completely :
The hole has been filled in.
3.
to spend time doing sth while waiting for sth more important :
He filled in the rest of the day watching television.
4.
to complete a drawing, etc. by covering the space inside the outline with colour