how come when people are praying they fold their hands?
It's a holdover from the origin of prayer, which originated as a form of supplication to human rulers, who demanded you approach them in a way which could not be threatening in any way (on the floor with your hands together in front of you facing down, the same thing you do if a cop is pointing a gun at you.)
Since gods were modeled after these human rulers, people naturally took on the same posture in regard to gods, and the tradition continues somewhat today.
As god concepts have evolved, god is no longer viewed as a super human living in the sky, but is now seen as a mysterious being living "outside spacetime" and yet simultaneously everywhere - so it isn't really possible to bow down to a god that's viewed as everywhere. A lot of people still kneel anyway.
Some people get on their knees to pray, or lay flat on the floor, face down, either way, I believe it indicates the humbling of ones self, in order to give honor and respect to the Father, also, indicates a laying down of ones will, in order to receive the will of the Father. However, there is no one way that is correct, I think we should follow the leading of the Spirit, at the moment.
I am not sure, but I think it is a sign of respect and reverence, and I also think its saying that "here I am Lord, I am focusing on You right now, I am keeping my hands together to keep from distractions" the Bible says BE STILL and know that I am God.
I've not not seen such but I know people bow there heads I do that too
you don't have to fold your hands you can do it all kinds of ways.
I dont I just bow my head in respect