Is it a must to replace battery at apple or apple authorise service provider?

[Guest Pipi]

If replace at 3rd party shop cannot?

[Guest Warranty]

If out of warranty can replace anywhere

[Steve5380]

You can do it yourself.  YouTube is full of videos showing how to service hundreds of electronics, appliances, cars, etc.   Like this one:

 

 

[lonelyglobe]

If got money to buy apple,  sure got money to go authorized dealer for servicing. Anything went wrong still can seek compensation.