How can I create a form that will be completed by 2 parties

I want to create a form that will requires 2 parties to complete - section 1 to be completed by me and then it gets sent to party 2 for their section of the form. 

You can take advantage of the edit link feature.

https://www.jotform.com/help/40-How-to-Let-Users-Update-Their-Form-Submissions-at-a-Later-Date

Create a notification email (https://www.jotform.com/help/25-Setting-Up-Email-Notifications). Add the other party as the recipient of this notification. Make sure that the edit link is added in the body of the email. When the form is submitted, the other party receives the email containing the edit link. The other party can click on the link to fill their part and re-submit the form. 

I hope this works for you. We also have this approval workflow: https://www.jotform.com/help/432-A-General-Approach-on-Building-an-Approval-Process-Workflow. 

I tried this as you recommended, however when party 2 received the form then the fields that were selected/completed by user 1 can be changed by user 2. Fields completed by user 1 must be locked so that it forces user 2 to complete only the rest of the fields since it was conditional to the fields of user 1. Otherwise user 2 can change user 1 fields and it overrides the conditions which defeats the purpose of the form. 

I think you could use the Get Form Page URL widget in order to know if the submission is being edited, then based on the result you could set the needed fields as read only. 

Here are the steps: 

1. First add the Get Form Page URL widget to your form, you will find it here: https://widgets.jotform.com/widget/get_form_page_url 

2. Add a condition that will allow you disable the fields, it should be like this one: 

This will allow your users to edit the submission, see the already submitted data, but will prevent the fields to be edited. 

This guide will help you adding the widget to your form: https://www.jotform.com/help/252-How-to-Add-a-Widget-to-your-Form 

I hope this helps.