Please follow the steps listed below:

• Go to Appearance > Customize > Typography Settings
• Go to Body Setting
• Select Primary Font Family, Variant Size, 
• Select Font Size and Body Line Height
• Select desired Body Color

• Select fonts for different headings

• Go to Appearance> Customize>Typography Setting>Widget Title Settings
• Select Widget Font Family, Variant, Widget Title Font Size and Widget Title Line Height

• Click on Publish Button