The bootup app function allows us to set a specific app to open automatically after turning on the device. You can find this option through the following steps.
Droid Settings→More settings→Device Preferences→Bootup app Setting.

Open the bootup app setting will display a list of all apps in the system. We only need to enable the app that we want to set for auto start.

It can work in conjunction with the auto-start application. When we need a specific app to remain open, if we accidentally close it, the app that maintains its state will wake it up and keep it in an open state. You can find this option through the following steps.
Droid Settings→More settings→Device Preferences→Keep alive app Setting.

Open the keep alive app setting will display a list of all apps in the system. We only need to enable the app that we want to set for keep alive.If the application is in the background or not started, it will be automatically launched to the desktop within one minute.