Hello, @BlueStyle,
Thanks for using our Theme and for contacting us.
Yes, you can use/add custom fonts from XStore > Custom fonts > Upload Your Custom Font.
Theme options > typography > headings
Check this topic https://www.8theme.com/topic/responsive-headings/
https://www.w3schools.com/cssref/pr_font_font-size.asp
https://www.w3schools.com/cssref/pr_font_weight.asp
https://www.w3schools.com/cssref/pr_text_color.asp
Regards 8Themes Team.