The fuel pump fuse on your 1996 Chevrolet C1500 truck protects the fuel pump relay and the fuel pump motor from electrical overloads. It is rated for 20 amperes and should not be replaced with a higher capacity fuse.
The fuse block that contains the fuel pump fuse is located on the left (driver's) side of the engine compartment. The wires attached to the fuse block should make it easy for you to identify.
The fuse block has a cover that must be removed for access to the fuses and relays mounted on the fuse block. Once the cover is removed, the relays and fuses can be seen and the fuel pump fuse located.
The fuel pump fuse is located to the right of the A.I.R. relay and to the left of the horn fuse. It is marked as the ECM-B fuse.