To find it, you'll need to:
1. Consult a repair manual: A Haynes or Chilton manual specific to your 1992 Jeep Wrangler YJ will have a diagram showing the exact location. This is the best way to ensure you find it.
2. Trace the fuel line: Starting from the fuel tank, carefully follow the fuel line towards the engine. The filter will be in-line somewhere along that path. Look for a small cylindrical metal canister or a section of fuel line that looks slightly different (perhaps thicker or with a slightly different fitting).
Be aware that working with fuel lines requires caution. Take appropriate safety measures and consider using a fuel line disconnect tool to avoid leaks or spills.