God the Father has never revealed Himself to mankind in any tangible or visual form, only ever as a voice from heaven; the Holy Spirit has appeared in the forms I mentioned above, at specific times and places.
Didn’t God appear to Abraham as 3 guests (3 aged men)?
1. Nothing is said about the apparent ages of these three men.
2. These three men from Genesis 18 are portrayed in Rublev's "Hospitality of Abraham/Holy Trinity" icon, one of the most famous icons in the Orthodox Christian world.