If you’re going from Android to Apple it’s very easy. Your contacts will sync straight away, download the apps for Gmail, Google Drive, Google Docs etc and you’ll be up and running in no time.
The advice I’d give if you get an iPhone is to use all the Google stuff for contacts etc rather than the Apple stuff. This makes it very easy to swap back to Android next time you need a phone, or just as easy if you swap iPhones.
There are a couple of things that Apple do well if you have other Apple devices, the ability to send texts from you Mac for example. There are a few minus points as well, apps that are free on Android often need to be purchased for example.
Having had both iPhones and Androids and being the owner of a Macbook and iPad, I prefer to use an Android phone, mainly because I can’t tinker around with a iPhone.
The thing that really, really annoys me with IOS is the app icons can’t be positioned in the same way as Android. Nexus for me every time.