Short answer. eBike tire pressure ranges from 20 to 65 psi depending on tire width and rider weight. Fat tires (4 inch) run 15 to 25 psi, plus tires (2.5 to 3 inch) run 25 to 40 psi, and standard tires (2 inch and under) run 45 to 65 psi.
Step by step
Check the sidewall. The tire sidewall lists min and max pressure. Never exceed the max.
Weigh the rider plus cargo. Heavier riders and cargo eBikes need higher pressure. Add 5 psi per 25 pounds over 175.
Adjust for terrain. Lower pressure for gravel and beach cruising for grip. Higher pressure for pavement commutes for efficiency.
Check weekly. eBike tires lose pressure faster than you think. A weekly top off improves range, ride feel, and pinch flat resistance.