You can generate voltage across a coil either by
(A). moving a coil through a stationary magnetic field,
(B). moving a magnetic field through a stationary coil.
Example: If you have 2 coils near each other, and one coil is running alternating current (which causes changes in magnetic field), you'll generate a voltage across the 2nd coil ... which is basically how transformers work. (B)
Another example: a coil moves/passes/spins through a stationary magnetic field, generating voltage across the coil... which is how a generator work. (A)