Font size
To change the font size you need to be familiar with CSS:
– Look at the stylesheet and find all reference to sizes.
– Make a note of all of the CSS selectors you need to target.
– Install this Custom CSS Manager plugin.
– Use its section of the dashboard to hold your CSS modifications.
– Create a new CSS style with the font size you want by targeting the CSS selectors you have gathered prior to installing the plugin.
Font type
To change the font type use this plugin
– https://www.ads-software.com/plugins/wp-google-fonts/
You can target particular page elements
– https://www.ads-software.com/plugins/wp-google-fonts/screenshots/