Leave a mark is a paper note in Fallout 76, introduced in the Skyline Valley update.
Location[]
The note can be found in the cellar interior at High Knob Lookout, on the ground near two paint cans.
Transcript[]
Lee - fixin up the place is one thing, but we also gotta leave our mark. You're the best at it... so ya mind givin this place the bird? All over. Thanks, owe ya one.
P