You'll likely need to get under the truck to find it. It's usually within easy reach, often close to the frame rail on the passenger side. It's a cylindrical canister, often metal or plastic.
To be absolutely certain:
1. Consult your owner's manual: This is the best resource for the exact location on your specific vehicle.
2. Use a repair manual: A Haynes or Chilton manual for your year and model will have diagrams and detailed instructions.
3. Search online: Search for "2005 Chevy Silverado fuel filter location [your engine size] [2WD/4WD]" on YouTube or a car forum. Many people have posted videos and pictures showing the location.
Important Note: Always be careful when working with fuel lines. Fuel is flammable and can be dangerous. If you are not comfortable working on your vehicle yourself, take it to a qualified mechanic.