You can change the font for the entire site's headings and body text from the Design settings under the Fonts tab.

For individual text boxes, you can modify the font, size, and style directly in the text box editor.

With the WYSIWYG editor, you can extensively customize the font for individual words, create lists, tables, and links. You can access the WYSIWYG editor from the settings of the content module, at the bottom of the </> HTML tab.