Using Elementors Site Settings > Typography styling option lets you style the headings used in your theme, but by default not on Elementor designed pages themselves

If you want them to apply to most of Elementor’s elements and widgets as well, you will need to disable Elementor’s default colors and fonts by going to Elementor > Settings and enabling “Disable Default Colors and Disable Default Fonts”.

The catch though is it will apply to all colours, which may not be what you want!