If you want to check that the battery change (Premium Pack) has been carried out, it is very simple:

If you have ordered a model lower than iPhone 8:

Go to Settings=> Battery=> battery status: the battery will show a status of 100 or 99%.

If you ordered a model equal to or greater than the iPhone X:

You have iOS 13 or lower: go to Settings=> Battery=> battery health: the battery will show a status of 100 or 99%.

You have iOS 14 and a model greater than or equal to the iPhone X:

Unfortunately Apple has disabled the battery status display if it has been changed outside of the Apple Store (which is the case on your phone). Therefore, you will see a message showing "repair" and then a message explaining that the iPhone cannot give battery health because the battery was changed outside of the Apple Store. No problem, you can check battery health in other ways.

There are many software available to check the battery level. We recommend the 3utool software, available on Mac and PC at the following link "http://www.3u.com". iTunes must be installed on your computer beforehand.