Hello, Global variables are variables that are simply created outside of a function. You do not need to specify anything specific. If you would like to create a global variable inside of a function you would use the "global" keyword, which then makes the variable belong to the global scope, down below is an example.
Example
If you use the global keyword, the variable belongs to the global scope:
def myfunc():
global x
x = "fantastic"
myfunc()
print("Python is " + x)
For referencing please refer to this website as it has many great solutions and answers to your questions:
https://www.w3schools.com/python/python_variables_global.asp
Also feel free to contact me also.