There are multiple ways to see what an application form (the Requirements section when creating) will look like to an applicant. 

If creating using the Form Designer Template, there is a specific function to preview as you create. Learn more here: Form Designer Template: Preview the Application Form

For opportunities made with other templates, you can use different options in the Manage view:

1. Click the Preview button. This will show all application fields and text boxes, but not Notes to Applicant.

2. Click the Submit by Proxy button. This will bring up the form that you use to apply by proxy. Type in an email address to begin filling out the form as an applicant would. To submit a test application, use your own email address or that of a colleague.

OR log out and...

3. Use a different user account (created using a different email address) to log in and apply. This will show you the exact experience an applicant will get, including what the form looks like, and any notes you've added will appear as tool tips when you start to fill in questions.