Parameters will as as a global variable. They can be accessed in the entire applications through code. By default, there are few global variables like UserId, Username etc. You can create any no. of global variables.
Note: Rules to be followed while creating global variables -
1. It starts with $$
2. It should not be a keyword.
3. Spaces and special characters are not allowed.
To create global variables, you can refer the Kushal help link https://erachana.in/software/define-global-variables-c-sharp