How to duplicate user modify their forms filled out it ??

Users can repeat their form

How can I do it ??

I'm afraid that I didn't fully understand your question.

1. If you want your users to make two or more separate submissions, they can simply open the same form again by using the same form link, such as this:

https://form.jotform.me/form/60191501055444

They can open the form, fill it out, and submit. Each time they fill out the form and submit this way, it would create a new submission.

2. If you want your users to update their existing submission, as asked earlier, it can be achieved by following this guide:

How to Let Users Update Their Form Submissions at a Later Date

If you were asking about something else instead, could you please clarify a little about what exactly you are looking for, and we will be happy to help. Thank you.