My iphone 6 is stuck on apple logo and it won’t turn on what should i do

Try a Forced Restart on the phone.

Force restart iPhone - Apple Support

Select iOS 12 in the Select iOS Version box

There are only 2 possible results when you perform a Forced Restart:

1) The phone returns to normal operation

Or, if the phone is still stuck on the Apple logo after a few tries......

2) There is a hardware problem with the phone that will need attention at the Apple Store (make an appointment) or take the phone to an authorized Apple Service shop.

You can find a list of authorized service shops in your area using the link just below:

Find Locations