How to add customized message in webform in frappe after submit in JS

Basically, I need to add my required message like " Your Job ApplicationNo-1234 " instead of Thank you for spending your valuable time filling out this form.

I have created Doctype of job application which connect the web-form with carrer where user will fill the job application form.

regarding this issue @rmehta sir to solve this problem and it will be more helpful for everyone.