how to lock apps in iPhone 7plus?

Use Restrictions on your iPhone, iPad, and iPod touch - https://support.apple.com/HT201304 - "You can use Restrictions, also known as parental controls, to block or limit specific apps and features on your iPhone, iPad, or iPod touch, including access to explicit content in the iTunes Store."

Use Guided Access with iPhone, iPad, and iPod touch

https://support.apple.com/HT202612 - "Guided Access limits your device to a single app and lets you control which app features are available."

Dear sir/madam,

Apple iPhone is already available in fingerprints sensors & passcode but this not access in other apps ( whatsapp, Facebook, Instagram).

As privacy anyone use the phone and get directly open the app and use personal massages and other,

So please enable this feature to use the fingerprint sensor in other applications.

mitulfromkadi wrote:

Dear sir/madam,

Apple iPhone is already available in fingerprints sensors & passcode but this not access in other apps ( whatsapp, Facebook, Instagram).

As privacy anyone use the phone and get directly open the app and use personal massages and other,

So please enable this feature to use the fingerprint sensor in other applications.

This is a user-to-user technical support forum. Apple is not reading here for suggestions. You can let Apple know what you'd like to see here:

Product Feedback - Apple

Note that no one can "use the phone and get directly open app" unless you give them the passcode to the phone.Do not hand over your unlocked phone to anyone you wouldn't give your wallet full of cash and credit cards to.

I want lock my all app

In iOS you can only lock an individual app if the developer of that app has enabled that feature in their product.

An iOS device’s built in security is the screen lock passcode and touchID or FaceID, which keeps anyone but you from accessing your device.

umair291 wrote:

I want lock my all app

Put a password on your phone. That will prevent anyone from accessing any of the apps.

Unless the developer of an app includes a locking function (most banking apps do), you will either have to lock the entire phone or lock nothing.