Locker

Locker is one of the most complete secure folder apps on the App Store. You can literally save anything inside the app.
Not only you can save pictures, videos, and files with Locker, but you can also hide apps from the home screen and save them inside the app’s library. It also lets you save and create notes from inside the app.
Locker has different ways to lock your device, you can use Face ID, Touch ID, or set up a PIN. But keep in mind that, like many other apps, if you forget your PIN number and you didn’t set up Face ID or Touch ID, you won’t be able to access the app at all.
There’s a catch, though, Locker is free to download but if you want to fully use it, you’ll have to subscribe to a monthly Locker Premium Pass. If you just want to try the app first, though, you can download it and use it for free for two months.