fill out

Short definition from Wiktionary

Verb

1. 1
   To complete a form or questionnaire with requested information.
2. 2
   To have one's physique expand with maturity or with surplus weight.
3. 3
   To fill up; to make full.
4. 4
   Used other than figuratively or idiomatically: see fill, out.

Noun

1. 1
   An option provided as one of a number of possible answers to a question in a form.
2. 2
   An extra car added to a freight train in order to achieve a minimum tonnage.
3. 3
   Something extra that is added to increase the size of something.
4. 4
   The amount by which a star in a binary system extends beyond its Roche lobe.