Where is computer located 1995 ford E-250 van?

There's no computer in the sense of a standalone PC in a 1995 Ford E-250 van. Vehicles from that era didn't have the complex onboard computer systems found in modern cars. The only "computer" would be the Powertrain Control Module (PCM), sometimes also called the Engine Control Module (ECM). This is a small, specialized computer integrated into the engine compartment, usually near the firewall. It controls engine functions like fuel injection and ignition timing.