Hello,
You can change the font by means of Advanced typography option, which allows to choose the item from a drop-down or insert your custom CSS class. Please navigate to the Theme Settings > Typography > Advanced Typography.
Here is the documentation providing more detailed instructions: https://xtemos.com/docs/basel/advanced-typography-settings-2/
You can set any style, provided you have uploaded the font, supporting this style. If your font is only bold, you would not find other options, You will have to upload all the fonts styles https://prnt.sc/r9fsz6
Best Regards