Apple logo blinking on screen automatically i don’t know whats happening

Thanks for the reply. That’s great that we can rule the battery out.

Please force restart your device: Force restart iPhone - Apple Support

If the issue persists, I suggest you have the device checked out at a Genius Bar or Apple Authorized Service Provider (AASP):

• Genius Bar Reservations: Genius Bar Reservation and Apple Support Options
• Locate Apple Stores & AASP’s: Find a Reseller 
• iPhone Service & Repair: iPhone Repair and Service - Apple Support

They will be able to do further testing and diagnostics on the device, and perhaps they can find out what may be causing this.

Good luck!

Hello!

What is the Maximum Capacity of your device’s battery? To find it, go to: Settings > Battery > Battery Health.