Since a free kick is a place kick, 2-16-4-b, c, and UIL Exception 27 apply, but I think makes sense to list them in a different order for explanation purposes:
c. A free kick place kick is a kick by a player of the team in possession while the ball is positioned on a tee or the ground. It may be controlled by a teammate. The ball may be positioned on the ground and contacting the tee.
b. A tee is a device that elevates the ball for kicking purposes. It may not elevate the ball’s lowest point more than one inch above the ground (A.R. 2-16-4-I). If utilized, a tee must be in contact with the ball for the kick to be legal.
UIL exception 27b changes the second sentence of b to read: It may not elevate the ball’s lowest point more than two inches above the ground (A.R. 2-16-4-I).
In c, the rule states a tee can be used on free kick place kicks, as long as the requirements in b are met - for UIL purposes, per the exception, this is 2".