Hey Karthikk! I’m glad you like the theme : )
The easiest way would be to define a font-family for the body (I think doing it in common.scss would be the best):
body {
font-family: 'The Name of your Font Family', [FALLBACKS];
}
I don’t know if you are adding your own fonts or picking up some google fonts, but, I would advise that you pick a family from the google catalog.
Remember to replace [FALLBACKS] with your fallbacks depending on what type of font you’ve chosen, you can see more on font-family fallbacks here
About changing the font for titles and headers, I think that’s the part that you already figured out, but as a reminder, besides from importing it you need to declare it in the line 116 of variables.scss
Hope it helps! have a nice weekend : )