As a Pact of the Chain Warlock, you:
…learn the find familiar spell and can cast it as a ritual. The spell doesn’t count against your number of spells known.
When you cast the spell, you can choose one of the normal forms for your familiar or one of the following special forms: imp, pseudodragon, quasit, or sprite.
The imp, quasit, and sprite all have the power to turn invisible.
Is it possible that when the Warlock calls forth their familiar, that the familiar starts in an invisible state? Or would they have to appear visible, and then immediately take an Action to turn invisible?