How do I make a player not move?

When players teleport to a map, how do I make them not move?

it can also stop them from moving if Their Walkspeed is 0 like this

local hum = findFirstChild("Humanoid")
hum.Walkspeed = 0

Hope I help:D

Aye, as Damo said, anchoring the player's torso is the best way to go, although you may want to disable the Animate script in the player's Character BEFORE anchoring their torso to avoid the ugly falling animation.