How would i make the players character change on textbutton click?

Don't try to access Server Storage via LocalScript as it will not work. Bcz Server Storage is accessable by server only.

This is not going to be a simple thing..

First, Local script in TextButton.

script.Parent.MouseButton1Click:Connect(function()
    game.ReplicatedStorage.YOUR_REMOTE_EVENT_NAME:FireServer()
end

Then, the Server script in ServerScriptService.

local function applyBodyColors(player, item, RigType)
    local char = player.Character
    item.Parent = char --Here, item is Body Color of the character
end

local function applyBodyPart(player, item, RigType)
    if RigType == "R15" then
        local replace = player.Character:FindFirstChild(item.Name)

        if replace then
            item.Parent = player.Character
            replace:Destroy()
        end

        player.Character.Humanoid:BuildRigFromAttachments()

    else -- If, the Rig type isn't R15

        for _, oldPart in ipairs(player.Character:GetChildren()) do
            if oldPart.ClassName == "CharacterMesh" then
                if oldPart.Name == item.BodyPart.Name then
                    oldPart:Destroy()
                end
            end
        end
        item.Name = item.BodyPart.Name 
        item.Parent = player.Character
    end
end

local function AddItemToCharacter(player, item, rigType)
    local Type = item.ClassName

    if Type == "Accessory" or Type == "Shirt" or Type == "Pants" or Type == "Hats" then
        item.Parent = player.Character
    elseif Type == "Tool" then
        item.Parent = player.Backpack

    elseif item.Name == "Head" then
        player.Character.Head.Mesh:Destroy()
        item.Mesh.Parent = player.Character.Head
        player.Character.Head.face:Destroy()
        item.face.Parent = player.Character.Head
        player.Character.Head.Color = item.Color

    elseif Type == "MeshPart" then
        applyBodyPart(player, item, rigType)

    elseif Type == "BodyColors" then
        applyBodyColors(player, item, rigType)
    end
end

local function loadCharacter(player)
    local Character = player.Character or player.CharacterAdded:Wait()
    local RigType = Character.Humanoid.RigType == Enum.HumanoidRigType.R15 and "R15" or "R6"

    local ReplicatedStorage = game:GetService("ReplicatedStorage")
    local NewCharacter = ReplicatedStorage:WaitForChild("Character")

    if NewCharacter then
        if player:HasAppearanceLoaded() == false then
            repeat until player:HasAppearanceLoaded() == true
        end

        player:ClearCharacterAppearance()

        local EquipCharacter = NewCharacter:Clone()
        for _, item in pairs(EquipCharacter:GetChildren()) do
            AddItemToCharacter(player, item, RigType)
        end
    end
end

game.ReplicatedStorage.YOUR_REMOTE_EVENT_NAME.OnServerEvent:Connect(loadCharacter)

It's too long I know and just don't copy/paste. Try to understand the script first.

Make sure to add Remote Event in ReplicatedStorage and rename it to that you will be using in the script.

Also, add the character u want to give the player in ReplicatedStorage.

Lemme know if it helps! Please do give an Upvote if it helped you bcz the script took really long time to write.

You need to (locally) clone CustomCharacter to game.StarterPlayer And then name it “StarterCharacter” and do Player:LoadCharacter()

COMBO of 2 Replies.

script 1: (localscript inside button)

script.Parent.MouseButton1Click:Connect(function()
    game.ReplicatedStorage.changecharacter:FireServer()
end)

script2(script inside serverscriptservice)

game.ReplicatedStorage.changecharacter.OnServerEvent:Connect(function(player)
        local ServerStorage = game:GetService("ServerStorage")
        ServerStorage.StarterCharacter:Clone().Parent = game.StarterPlayer
        player:LoadCharacter()
end)

Works! Thanks iOwn_You and BestCreativeBoy