Checkbox Custom Field

To make changes to fields, or to add or remove fields, you can 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/

You could also 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.

However, we aren’t able to help with custom code requests like this. 🙁 You may want to look into one of these services for help:

https://codeable.io/

http://studio.envato.com/

https://jobs.wordpress.net/

Sorry I can’t be of more help here!