New to CPA please help me! (checked all threads but couldn't find my solution)

You'll want to specify in your application that your primary promotional method will be email marketing.
Be prepared to explain where you collect your opt-ins, what email service you use (i.e. aweber) and also that you are going to be using this method only for offers that allow email as one of the promotional methods and that you will be applying any applicable advertiser suppression list.

What you put in the website URL box of the application is far less important than the additional information you provide in comments and discussion with them.

It is, however; important that the URL that you provide in the application WHOIS information matches your personal information provided on the application.

You may find it helpful to join multiple networks, as virtually everyone experienced in CPA would agree that you should have multiple networks available to you.

As always, reach out to the networks upon submission of your application to discuss your promotional methods and campaign plans.