Hi marketerjahidul,
Thanks for reaching to us and appreciate your patience.
1. In order to add Custom Fonts, please read documentation for more details https://xtemos.com/docs-topic/how-to-upload-custom-fonts/
About the disable fonts, please describe in details and I can assist you better.
2. After upload Custom Fonts, then navigate to Theme Settings > Styles and colors > Buttons and scroll down to Advanced button styles area and assign to specific buttons https://prnt.sc/huwNQixwY1sZ
Please read our article https://xtemos.com/docs-topic/advanced-button-styles/
Regards,
.
