The punch list comes at substantial completion. The contractor must fix each item before final payment. Retainage often stays held until the list is closed.
Typical items are small. A scuffed wall. A missing cover plate. A basketball backstop that does not winch up evenly. A door that does not latch.
An estimator does not price a punch list line by line. Carry some labor for return trips and touch up. The amount depends on the trade and the job size.
Read Division 01 for the closeout steps. Some specs set a deadline for punch list work.