Can you save game progress on the Vita?

I’m new to emulators and homebrew. I believe I have RA installed correctly. I have SNES and Sega emulators installed on my Vita so far.

Just curious how I can make the games full screen? Every game is just a small box in he middle of the screen, is that normal?

Last, is there any way to save your progress in a game yet? I was playing Super Mario World and there was no way for me to get to any time of menu? I tried every button.

Thanks for the help!