You do not explicitly state that you have all your text selected, but you must do that first if you're trying to change the font face for text that's already written.
Once that's been done, CTRL + D or CTRL + Shift + F will open the Font dialog where you can choose font face, size, and other attributes.
Brian - Windows 10, 64-Bit, Version 21H2, Build 19044
Here is a test to find out whether your mission in life is complete. If you’re alive, it isn’t.