Can I add the page break option of two forms after I have created the one single form to utilize the save for later feature?

I just sent a question in about the save for later feature. And of course there was my answer after I submitted. Bu my question now is, I have already completed a pretty involved form, can I add that name and email and page break on an existing form?

Yes, you can indeed add the page break to split your form and it does not matter if you have already fields to your form, here is also a guide that will help you to create a multiple pages form: https://www.jotform.com/help/119-How-to-Create-Multi-Page-Forms 

Please if you have any question, let us know.