Creating a game chat function which detects a specific Player?

game.Players.PlayerAdded:connect (function(player)
	player.Chatted:connect(function (msg)
		if msg == "Material" then
			game.Workspace.BaseDoor.Material = Enum.Material.Plastic
			game.Workspace.WallA.Material = Enum.Material.Plastic
			game.Workspace.WallB.Material = Enum.Material.Plastic
			game.Workspace.Walls.Material = Enum.Material.Plastic
		end
	end)
end)

This script currently does the list below 'then' once a player types in chat "Material" but the problem is, anyone can call this command in chat. How can I make it so only specific players can call this command?

You already have the player variable specified for you when the player joins the game and the script handles it in the first line. Simply add a clause to the if statement to check if the player name is the specific one you want.

player_name = "EasilyTech"

game.Players.PlayerAdded:connect (function(player)
    player.Chatted:connect(function (msg)
        if msg == "Material" and player == player_name then --Checks if it is you that chatted "Material" and then proceeds
            game.Workspace.BaseDoor.Material = Enum.Material.Plastic
            game.Workspace.WallA.Material = Enum.Material.Plastic
            game.Workspace.WallB.Material = Enum.Material.Plastic
            game.Workspace.Walls.Material = Enum.Material.Plastic
        end
    end)
end)

Expanding on MrLonely1221's post, you could also use a table to be able to accomplish this:

local PlayersWhoCanUseCommand = { -- The table which will be used later on
	['EasilyTech'] = true, -- This will be checked to see if the name is in the list later on
	['N00B'] = true
}

function onPlayerJoin(plr) -- I liked to keep my code kinda neat ;P onPlayerJoin is a function, and variable 'plr' is used to represent a player that has connected to the server
	if PlayersWhoCanUseCommand[plr.Name] then -- If the player's name is in the list, then it will return true & execute the following chunk, if not, well, you know
		plr.Chatted:connect(function(msg) -- Fires whenever a player chats; variable 'msg' is used to retrieve & return the player's chat
			if msg == 'command' then -- If the chat is 'command,' or the player chatted 'command,' it will return true & execute the following chunk
				print('Command fired') -- Prints into the Output
			end -- Ends the chunk
		end) -- Ends the function/event-chunk
	end -- Ends chunk
end -- Ends chunk

game.Players.PlayerAdded:connect(onPlayerJoin) -- Whenever a player connects to the server, the 'PlayerAdded' event will fire (Will only work in sever-scripts), and also fire & return the player, which is why 'plr' was added in the 'onPlayerJoin' function

Imo, I believe that's the best way to go about tables w/ chat commands: it's much simpler, and easier to use rather than having a for loop loop through a table & return a bool.

I haven't scripted in months, so I hope I helped you somehow. :)

local admins = {"EasilyTech", "yourbestfriend", "yourreallybestfriend"}
local banned = {"someoneyoudespise"}
game.Players.PlayerAdded:connect (function(player)
for _, s in pairs(banned) do
if player.Name == s then
player:Kick("#Banned") --Remove banned players
end
end
    player.Chatted:connect(function (msg)
for i, v in pairs(admins) do
        if msg == "Material" and player.Name == v then --If player's name is anyone at the table 
            game.Workspace.BaseDoor.Material = Enum.Material.Plastic
            game.Workspace.WallA.Material = Enum.Material.Plastic
            game.Workspace.WallB.Material = Enum.Material.Plastic
            game.Workspace.Walls.Material = Enum.Material.Plastic
        end
end
    end)
end)