To be absolutely sure, I recommend:
* Checking your owner's manual: This is the best resource for the specific location on your truck.
* Looking online for a diagram: Search for "1998 Dodge Ram 1500 fuel filter location diagram" on Google Images or a similar search engine. You can often find pictures showing the exact location.
Be cautious when working near the fuel system. Fuel is flammable, so avoid sparks or open flames.