How do I lock my photos on my iPhone 7?

How do I lock my photos on my iPhone 7?
Use the following steps to see how.

Open your Notes app.
Create a new Note.
Tap the camera icon above your keyboard.
Tap “Choose Photo or Video”
Select the photos/videos you want to lock, and tap “Add”
Tap the three dots icon in the top right of your Note.
Tap “Lock”
You’ll be asked to create a password for your Note.

Use the following steps to see how.
  1. Open your Notes app.
  2. Create a new Note.
  3. Tap the camera icon above your keyboard.
  4. Tap “Choose Photo or Video”
  5. Select the photos/videos you want to lock, and tap “Add”
  6. Tap the three dots icon in the top right of your Note.
  7. Tap “Lock”
  8. You’ll be asked to create a password for your Note.