Password protected folder

Enable guided access first or don’t lend your device.

Use Guided Access with iPhone, iPad, and iPod touch - Apple Support

Access to the (single-user) iPhone is protected by biometrics and passcode, and the data itself is encrypted using the passcode.

Sharing an iPhone and sharing an Apple Account tends to end badly.

Given iPhone is single-user, adding a password to protect password-protected data seems less than useful generally, though.

But if you really want that, you can require Face ID for opening Files app. Then everything is locked.

One other option that is supported is SMB server access, so you can place your data on a server you control, and then password-protect that.

Notes and whatever is stored in those can also be locked, as well.

The amount of destruction the little people have caused their parents and grandparents is, way, way, way, way, way beyond files. Precious photos permanently gone, mail threads gone, settings changed, passwords compromised, subscriptions canceled, and that’s all before hardware damage and destruction. And yeah, they can access or delete files, too. If you are going to share a device, expect to get your data rummaged, and quite possibly rubbished.

Send Apple feedback: Product Feedback - Apple

skbadwal wrote:

Sometime people have to give phone/mac to our kids

The kids require their own Apple Account.

Make sure that each family member has a unique Apple Account - Apple Support

Or see the excellent suggestion provided by muguy as well as MrHoffman’s response.

From my experience, when a particularly successful 3rd party app catches Apple's eye (see what I did there?!), it's often a matter of time before said app ends up being included in a future iOS build... The weather app 'Dark Sky' is one recent example... Currently, the latest iOS includes a 'Passwords' app, that seems to rival the 1Password app...

A password-protected folder option could very well be a few builds down the road...

Folders are already protected, as your Apple Account and password are required to access your information. And of course Apple Accounts should never be shared.