There are many apps that can lock your apps. But they do have ads or you have to buy a subscription. Tasker lets you lock down specific apps.
Follow the below steps;
- Create a new Profile and select Application.
- Choose all the apps you want to lockdown.
- Return to the Profiles tab, and add a new task and name it.
- Select Display, then tap Lock.
- Type in the code you want to use to lock those apps.
Now, any time you open those specific apps, you will need to type your password to launch them.
Read Also: Enable Pixel 3’s Flip to Shhh Feature on Android with Tasker