I don't know how to charge MCash?

Q: I don't know how to charge Mcash!

A: You can charge MCashin the game.

Once you go in game, please go to any weapon shop.
You will see a yellow button on the top left corner, indicated with a
red box in the screen shot below.
A window will pop up and guide you through the steps. Simply follow the instructions and you can charge MCash!