|The following is based on Fallout Shelter and some details might contradict canon.|
“Comes with a side of lip, a sprinkling of sass, and a bottomless cup.”— In-game description
The waitress uniform can only be worn by female dwellers. It provides the wearer with an additional 4 points to Agility.
Found in lunchboxes only.
If successful attempt disassembly of outfits you can get junk:
Waitress uniform (1)
Free space in the storage room