Each job on Mingle has a separate page where candidates can apply. This page contains the job description and application form.
You can customize it from Settings > Application form
You can find here more details on how you can customize the form according to your needs: Customize the application form
To see how the form that will be shown to candidates looks like, go to the careers page. For this, in the menu of Jobs click on Visit your careers page which appears in the upper left, under the title Jobs
Once on the careers page, click on the button Details next to the job you want to view.
The application form is on the right side of the page and contains all the fields that you have configured on the form page in the Settings.