How can I find my jotform's id?

just that, where i can find the jetform id for use it in adobe muse widget

I believe you mean you'd like to locate your jotform's ID and use your form in adobe muse.

The form id is actually the string of numbers located at the end of your form's direct url.

Example:  http://www.jotform.co/form/63151134044847 

The number from your form above "63151134044847" is the form's id.

However, since you mentioned you want to use your form on adobe muse I'd like to let you know that we have a guide for that here https://www.jotform.com/help/99-Adding-a-form-to-Adobe-Muse.