Tinted has color when it goes on immediately which is supposed to help you apply without making errors. I like tinted for face, and untinted for body since the tint can come off on clothing.
Untinted means there is no color guide to assist with application. Tint in the fake tan allows you to see where you have applied it and to minimize application mistakes. The tint washes off when you initially shower, leaving behind the color of the fake tan product itself. Gradual tanners are more forgiving than tanners that give full color with one application, because application mistakes made with a regular tanning product will be very noticeable and hard to correct without removing and reapplying color. Pro-tip: If it is your first time using a fake tanning product, use one with a tint or color guide to avoid embarrassing white patches of skin you accidentally missed. (P.S. I have been fake tanning for years and I would still be uncomfortable using a product without color guide.)