This app was mentioned in 4 comments, with an average of 1.25 upvotes
I don't know if it's exactly what you need but I use an app called <em>ClevNote</em>
It's just a regular 'ol note taking app.
HIPPA requires all sensitive information to be stored behind two locks, and the app has settings where you can set it up to require a password to enter the app, then you can set folders and set each folder to require an additional password to gain access.
You can also set it to back up notes to Google Drive and can restore the notes on another device. It's really handy if you juggle multiple devices for work like I do.
I love it.
ClevNote is the best.
Try ClevNote