Getting message

[orangeleaf]

Showing message check the background activity.but there is no back ground activity available 

[Mehz]

Its a virus . Go to setting then app u will find like this blank app uninstall it

[umesh30]

Go to Settings > developer options > Running services and find out this app which is running in the background without app icon.

[PrajwalKasture]

Restart karo

[PrajwalKasture]

Which Sim using

[orangeleaf]

Airtel and jio

[Hunter55]

Go to settings and in apps you will see an application without name and the profile uninstall it.
If not found then apply filter of show system apps.
See there will be empty space between apps it is showing click on it and uninstall it.