How to add data to generated mongodb document?

Question

Node.js

React, Node, Mongodb website.
For example, there are three pages with forms.
Receiving data on the first page, when you click on the button, the data is sent to the server, processed and written to the database (a new document is created in the collection), and the transition to the next page occurs.
On the second page, we also receive data, send it to the server and .....

How to add data to the document that was created when sending data from the first page?
How to assign a document from the mongodb collection to each user?

Answer 1

Found a solution.
I don’t know how correct, when you first visit the site, the id is stored in session storage, and when creating a document, this id is written to the document.
Then, with further additions of data, we look for a document by this id.

Answer 2

There is more question in 1, according to the structure of the database tables. Q2 Can only registered users submit these forms? In 3 mungus, this is not a relational database, but it has its own features, how to get around all this