Vibrato

An LFO (low-frequency oscillator) is an oscillator too slow to hear as a tone. Instead of making sound, it moves a control up and down in a repeating cycle. Here it moves the pitch of a long note.

LFO>Pitch is how far the pitch moves, in semitones. A little is a gentle vibrato, like a singer; more sounds wobbly and seasick.

LFO Rate is how many cycles per second. Around 5 Hz sounds natural; slow rates sound like a drifting tape, fast ones like a trill.