"Make a NPC that follows you"

-- server script (ServerScriptService) 
local pfs = game:GetService("PathfindingService")
local npc = game.Workspace.NPC
local followDistance = 10

local function followPlayer(player)
    local character = player.Character
    if character and character:FindFirstChild("HumanoidRootPart") then
        local path = pfs:CreatePath()
        path:ComputeAsync(npc.HumanoidRootPart.Position, character.HumanoidRootPart.Position)

local waypoints = path:GetWaypoints()
        for _, waypoint in ipairs(waypoints) do
            if (npc.HumanoidRootPart.Position - character.HumanoidRootPart.Position).Magnitude > followDistance then
                npc.Humanoid:MoveTo(waypoint.Position)
                npc.Humanoid.MoveToFinished:Wait()
            else
                npc.Humanoid:MoveTo(npc.HumanoidRootPart.Position)
            end
        end
    end
end

game.Players.PlayerAdded:Connect(function(player)
    player.CharacterAdded:Connect(function()
        while true do
            followPlayer(player)
            wait()
        end
    end)
end)