Respondent Registration to group of forms

We have 3 use cases for forms. 1) Initial Request Questionaire 2) On Boarding Documents 3) Reservation/Payment. 

I was wondering if JotFrom has the ability to has the ability to create a log in environment where respondents can register to access additional forms. i.e. log in to onboard.jotform.com and will have access to on boarding documents and reservation document. 

I'm not sure if I understood correctly your question, but seems like you want to allow your users to save the info they have entered so they can come back to the form and simply complete it. 

If I'm correct then you could follow this workaround that will allow your users to save the data previously entered and then come back to the form using a custom URL to complete it, here is the link to the guide that will help you with this feature: How-to-Save-Forms-and-Continue-Later

As there is no a way to allow users to log in without creating an account on JotForm, this would be a good workaround to help you to save info entered and continue the form on a later time. 

However, you may provide us more details about what you're looking for, we will be glad to help you.