How can I create a Unique customer order id once someone click at the submit button?

My second query is when someone clicks "Submit" I want to create a unique customer Order ID 

Please refer to these links to know how you can generate unique id once a submission has been made.

https://www.jotform.com/help/79-How-to-Add-Custom-Unique-IDs-to-your-Form-Submissions

https://widgets.jotform.com/widget/autoincrement

Hope this will help.

If you have any further query, please let us know.

Thank you that was really helpful. 

How can I add that unique ID to the thank you page and display the thank you message on the same page where the form is displayed without redirecting. Please let me know this is done

My understanding is that you want to add the Unique ID value in the Thank You Page. 

You can do this in the Thank You Page Editor. Just click the "Form Fields" dropdown and select the Unique ID option. This will generate the unique field name automatically.

Here's the result:

Related guide: https://www.jotform.com/help/211-Setting-up-the-Thank-You-Page

Hope that helps. Thank you.