Advance payment is a paper note in Fallout 76, introduced in the Expeditions: Atlantic City update part one, Boardwalk Paradise.
Location[]
The note can be found in the basement level of the Neapolitan Casino in Atlantic City. It is in a room next to two large generators, on a cabinet across from some consoles, next to a walking cane spawn. It is in the same room as the note power consumption report, which is on a desk nearby.
Transcript[]
Attached is the advancement for your cut of the job. You'll receive the rest after the haul has been lifted and flipped.
At 9:00pm exactly on the night of the job, kill the power. We'll need about 8 minutes to clear the vault, and lift the crate. You do whatever you need to keep the power off during that time if you want your full cut.
Burn after reading.
-AM