Definition from Wiktionary, the free dictionary
An ellipsis for "I will do (it or that)."
- Used other than as an idiom: see will, do.
- Affirmative yes in response to an especially personal or direct request for the performance of some action.
- Could you wake me when you get up? — No problem, will do.
- Make sure you understand this before the next class. — Will do, for sure.
- One of us needs to verify the source. — Will do, but I could use some help.