How to teleport all players to a location in game?

local Location = CFrame.new(0, 50, 0)

for i, v in pairs(game.Players:GetPlayers()) do
    v.Character:SetPrimaryPartCFrame(Location)
end

Are you talking about a teleport IN GAME, or a teleport to another place?

In case of a place in game, here you go.

Put this inside a locascript, then put the localscript inside StarterGear.

player = game.Players.LocalPlayer

repeat wait() until player.Character.HumanoidRootPart

humpart = player.Character.HumanoidRootPart

humpart.CFrame = CFrame.new() -- Position Of A Part

This is probably the easiest way (I didn't test it with FilteringEnabled):

_Players = game.Players:GetChildren()

for x = 1, #_Players do
    _Players[x].Character:MoveTo(Vector3.new( Position ))
end