Some custom work needed for submitting an application

What would take to develop a custom login screen that pops up when someone clicks the apply button on a job. That screen would be a popup with the following fields

E-mail address

Last name

First name

Upload CV

Indicated as Optional fields:

Cover letter upload

Comments field

Button Apply

Then once submitted, we save the application to the backend and email the details to the employer.

It should also be easy to edit the text that's show on that popup, for example change the header of the popup e.g. Apply to "XXX name of the job". We are ok with editing thru hooks in functions.php, we don't need a specific interface for doing that.