can I change all headings fonts to open sans condensed font?

You need to define all h1 ,h2…h5.. headings classes with new font family which you want.

add this css in custom style .
You should not edit your theme’s files directly when adding CSS as any direct changes will be lost when it comes time to update your theme.

Instead, set up a child theme or activate a custom CSS plugin. If you have Jetpack installed then you can enable its custom CSS module.

problem solved thanks seemas05