The button is given below, which you have to press to open the phone in the GTA 4 PC game. Once you open the phone, you can use it according to your needs.
Steps to open Phone, Close Phone
- Press the Up arrow button to open the phone, then Press the Up arrow again to open the dial pad. (Please Note – if you have not completed any missions, please first complete 3-5 missions, then try otherwise Dial pad not come in the phone.)
- you can Press Backspace or Right click on the mouse for Back/for the closing phone. (Note: You may have to press multiple times for going back and for closing the phone.
- Now for entering cheat codes in the form of numbers, you have to open dial pad, after opening dial pad you can enter cheats in the phone. (Note: Press arrow keys for moving the highlighter and Press Enter for pressing numbers)
- After writing all numbers, press the enter key to dial the number.
Visit here If you want to activate cheat codes of GTA 4 without reentering the cheat.