To change Typography, we can go to Theme settings > Typography tab, where you can change the font family of headings and body texts to use universally. The styling of headings and body texts will follow default styling of the chosen font family.
To change content for Heading, click on the Heading element from each section.
To change content for body text, click on the Body Text element from each section. Parts of Body Text can be edited separately, using the menu bar on the top of the content box.