how do i recover a note that I forgot the password for

From the article below.

If you forgot your notes password

To unlock a note, you need to enter the password that it's locked with. If you forgot the password, Apple can't help you regain access to your locked notes. You can create a new password, but this won’t give you access to your old notes. A new password will let you password protect any notes that you create going forward with the new password.

Notes - How to lock on your iPhone, iPad, and iPod touch.