Will the 4.6 liter engine from a 1995 Ford Thunderbird fit 1998 F150 that has bad engine?

No, a 4.6L from a 1995 Ford Thunderbird will not be a direct fit into a 1998 Ford F-150. While both are Ford engines, the Thunderbird's engine is likely a modular engine designed for a front-wheel-drive or transversely mounted application. The 1998 F-150, being a truck, uses a longitudinally mounted engine, typically a larger displacement V8 designed for heavier duty applications. The mounting points, accessories, and even the transmission compatibility will be significantly different. You'd face major modifications, and it's unlikely to be a cost-effective or practical swap. It would be far more sensible to source a used engine more suitable for the F-150.