I've installed emacs with f-droid and I'm trying to increase the font size, but it says the font is not available no matter what i try.
Is there a package that needs to be installed? All in trying to do is increase the size;)
First you should find out what the various font faces are through browsing the Customize drop down menus.
Options > Customize Emacs > Browse Customisation Groups > Faces ... Etc
Once you know which face you want to customize, use the menu again to navigate to Specific Face. Most likely you want to customize the default face first.
Options > Customize Emacs > Specific Face
A minibuffer prompt will appear at the bottom of the screen. Type in default
then hit return
and all the settings for the default face will appear in a buffer available for you to change. The default font size on my phone was 119 so I changed it to 160.