https://support.apple.com/itunes
Also, be aware that an iPad 4th generation is an over 7-year old device that cannot be upgraded past iOS 10.3.3/10.3.4.
As of tge beginnjng of 2019, many third party app developers have stopped supporting 6, 7, 8 and 9-year old iPad models running iOS 10 and earlier.
So, finding compatible apps, for initial download from the iOS App Store, for that iPad 4, will be a challenge, now.
Sorry. It is what it is at this very late date.
If you need an iPad that can run the latest and greatest versions of iOS, as well as, the most current apps available, then, you will need to purchase a new iPad from Apple or a discounted, refurbished iPad from Apple’s Refurbished & Clearance section of Apple’s Website.
Best of Luck to You!