What are Local Variables?

Local variables are basically, variables that run on it own scope. And local variables are good practice to maintain code for global variables

If you still don't understand click here

Also here's an practical example of using local variables

Scope

function createPart()
   local part = Instance.new("Part") 
end

This will run in its own scope. The way to tell wether it will happen in it own scope is to check whether there's a function of there s s function then that means it's going to happen in its own scope

Global Variables Global variables are variables that can be used anywhere of your script. They don't have to be accessed through a function Here's an practical example of how to use it

local part = script.Parent -- can be used anywhere in your script.

Make sure to accept my answer if it helped.

For example:

local part = script.Parent -- Even though it says local its actually global
part2 = workspace.Part2

Those are Global Variables. They can be used ANYWHERE in the script.

Local Variables:

function createPart()
   local part = Instance.new("Part") -- This is a local variable. It can be used only within this function
end

Another Example:

if bool = true then
    local bool2 = false -- Local Variable
end

Last Example:

part = script.Parent -- Global variable

function doSomething()
end

Hope this helps! Sorry if you can't understand.. It might be a little tricky for new scripters!