I forgot my notes password. So I created new notes under a different password. How can I get the password to the old notes that are still locked?

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. 

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

You don't. You can keep trying until you guess correctly.

Try to get password I my phone for a app that I use

I forgot my password to my notes how can I reset it

My old iPhone is out of order,

I bought new iPhone but I forgot my old notes password…

I reset my password but it’s still not working, plz help me out of this.

Resetting your password only changes it on new notes. You can only access your old notes with the previous password.