Hot tub filling

I want to fill my wood fires Hottub with a gravity feed waterline. I have the tub half in the floor and half out. I don’t want the feed line to come above the floor. My question is will it fill the tub if I put the line down low or do I have to have the outlet above the water and let the water fall in the tub? I have plenty of “head” of water on the height I want in the tub. Basically with lots of head pressure will water push up to a height or does the water have to fall? Hope This makes sense.

either way will work

It will be fine from the bottom as long as the height of the source is higher than the top of the waterline in the hot tub.