I will help you but from now on you have to only post about actual Scripting problems, that you have, read the guidlines please or you will get shutdown, this is what you need to do

local Player = game:GetService("Players").LocalPlayer --// This gets the localPlayer, this is your Player
local Character = Player.Character or Player.CharacterAdded:wait() --// This gets your Character
game.Players.PlayerAdded:Connect(function() --// This fires when someone eneters the Game
   if (Character) then --// Checking if the Character exists
      local CharacterParts = Character:GetChildren() --// Getting everything inside of the Character, hats etc..
      local BodyParts = {} --// empty table for filling in specific things inside the Character
      for _,BodyPart in ipairs(CharacterParts) do --// Going throu everything inside the Char
         if (BodyPart:IsA("BasePart") then --// Statement that tell us if it's a BodyPart or not
            table.insert(BodyParts, BodyPart) --// If is out in table
         end
      end
      for i = 1,#BodyParts do --// Loops throuh everything
         BodyParts[i].Transparency = 0; BodyParts[i].CanColide = false --// Sets the things to make you a "ghost"
      end
   end
end)

Hope this helps you out, I would love to be more specific but you understand that this goes against the guidlines so I shouldn't be exactly helping you out

For you case, you need to use a generic for loop and :GetDescendants() to get all in character.

--< Script, ServerScriptService >--
game.Players.PlayerAdded:Connect(function(player) -- Get player on join in game
    player.CharacterAdded:Connect(function(char) -- Detect character of player added

        player.CharacterAppearanceLoaded:Wait() -- Wait for load all in character

        for i,v in pairs(char:GetDescendants()) do -- Get all in character
            if v:IsA("BasePart") and v.Name ~= "HumanoidRootPart" then -- Check if value(descendant) is a basepart and name of value(descendant) not is HumanoidRootPart
                v.Transparency = 1 -- Set transparency to 1
                v.CanCollide = false -- Set cancollide false
            elseif v:IsA("Decal") then -- Check if value(descendant) is a decal to hide player face
                v.Transparency = 1 -- Set transparency of decal to 1
            end
        end
    end)
end)

Explaining:

• For loop
  • Generic The for loop generic basically get all in a table with index,value i = index v = value example:

for i,v in pairs(workspace:GetDescendants()) do -- Get all objects in Workspace
    print("Position in table: " .. i .. "\nBlock name: " .. v.Name)
 end

• Numeric The for loop generic basically get all in a table with index, for get objects you need to use location:GetDescendants()[INDEX_NUMBER] i = index
  • example of how to use the numeric for loop: for iterator_variable = start value , end value , increment do

Example:

local location = workspace:GetDescendants() -- Location with :GetDescendants()
for i = 1,#location do
    -- What is the #location, this basically get length of a table.
    print("Position in table: " .. i .. "\nBlock name: " .. location[i].Name) -- Getting object with location[i] (location = location:GetDescendants())
end

• GetDescendants
  • Returns an array containing all of the Instance's descendants Running this function will collect every object descending from this Instance and return them in an array For access the table you can use for loop(Generic/Numeric)

Example:

for i,v in pairs(workspace:GetDescendants()) do
    print(v.Name) -- Print name of all descendants in workspace
end

• player.CharacterAppearanceLoaded:Wait()

Basically wait for all in character load.

Hope it helped :)

Wiki pages:

CharacterAppearanceLoaded

For loop (only numeric)

GetDescendants

PlayerAdded

CharacterAdded