Add language filter in job listing

For field changes, or to add or remove fields, use functions and/or filters inside a functionality plugin:

https://wpjobmanager.com/document/editing-job-submission-fields/

https://css-tricks.com/wordpress-functionality-plugins/

Here’s an example tutorial:

https://wpjobmanager.com/document/tutorial-adding-a-salary-field-for-jobs/

… that’s similar to what you’re asking for.

You also might use a third-party plugin such as WP Job Manager Field Editor:

https://plugins.smyl.es/wp-job-manager-field-editor/

… which has a nice GUI for editing fields. ??

Thanks!