The Starter Relay was on the inner fender on older Fords, but it was often called the starter solenoid.
Just like core hole plugs are often called Freeze Plugs, "A rose by any other name........."
But yes, as said above, the starter relay/"starter solenoid" is on the starter motor now.
And just FYI, a solenoid is usually an electro/"mechanical" device than when activated by electrical current physically moves an external mechanism.
Many starter motors have a solenoid on them, when electrical current is applied the solenoid pulls on a lever that moves the starter motor gear toward the ring gear, and engages the starter motor with the engine.
A Relay when activated by electrical current connects and/or disconnects other electrical connections(this more accurately describes Fords inner fender mounted device)