How to change a character's position?

This is how you teleport or change the players position. We can use 3 different things to teleport. 1. CFrame, 2. MoveTo, 3. SetPrimaryPartCFrame. I know you already accepted an answer but most people don't know that there are 3 ways to teleporting a player.

CFrame. This is easy.

workspace.Player.Torso.CFrame = CFrame.new(0,0,0) --Teleport

Next is moveto function,

workspace.Player:MoveTo(Vector3.new(0,0,0)) --Moves the model

Last is SetPrimaryPartCFrame

workspace.Player:SetPrimaryPartCFrame(CFrame.new(0,0,0)) --Teleports the primary part and also teleport the objects in the model.

I hope it helps!

To teleport ALL the players, do this:

for i, player in ipairs(game.Players:GetChildren()) do
   if player.Character and player.Character:FindFirstChild("Torso") then
      player.Character.Torso.CFrame = CFrame.new(0,0,0) + Vector3.new(0, i * 5, 0)
   end
end

Teleports each player and teleports each player on top of each other so they don't get stuck inside each other.

If you want to teleport players from a game to another game use the TeleportationService. For example:

script.Parent.Touched:connect(function(hit)
    local player = game.Players:GetPlayerFromCharacter(hit.Parent)
    if player then
        game:GetService("TeleportService"):Teleport(8473728, player) --Teleport the player to a game with an ID of 8473728
    end
end)

This is what you use for GUIs. THIS IS FOR LOCAL SCRIPT ONLY.

script.Parent.MouseButton1Click:connect(function()
    local player = game.Players.LocalPlayer --LocalPlayer
    if player then
        game:GetService("TeleportService"):Teleport(8473728
    end
end)

Use the MoveTo() method.

Character:MoveTo(Vector3.new(0, 0, 0))

Make sure to define Character and stuff, and you can of course replace the Vector3 values.

EDIT: You could also use CFrame, but that's if you're teleporting to a part. If you need a tutorial on CFrame, just comment.

character.HumanoidRootPart.CFrame = CFrame.new(0,20,0) --where character is a reference to the player's character, and CFrame.new() contains the desired position