Not only is it possible, but you should use the same AppleID for all your devices. Your AppleID is the account to which all your devices are associated - and all App, iCloud, Media and Subscribed Apple services are linked.
Using the same AppleID allows you to pay-once - and share your Apps and subscriptions between all your devices.
An AppleID is yours for life - as all all purchased content is permanently linked to the account from which it is purchased. Over time, you find it necessary to change your primary email address (your AppleID username - that you use to sign-in). This is a simple process, as are changing and updating your secondary (recovery) email addresses and trusted telephone numbers - all of which you should diligently maintain. Should it be necessary to restore a device, resolve a forgotten device Passcode or AppleID Password, you’ll need access to these important credentials and communications tools.
Synchronising your devices via iCloud services is very easy. iCloud is a principally a synchronisation and backup service - but also provides cloud storage for other data. You can also access some resources - such as your Apple Calendar, Contacts, Reminders, Notes and “Find Me” services from any web browser.
What is iCloud? - Apple Support
Set up iCloud on your iPhone, iPad, or iPod touch - Apple Support
https://www.imore.com/icloud
We very wary about choosing a device with limited internal storage - in particular the very lowest storage tiers. Internal storage cannot be expanded or upgraded - and iCloud storage is not a substitute for adequate local storage.
Remember, iCloud is principally a synchronisation service - allowing files to be shared between devices whilst keeping a copy in iCloud storage. This copy allows data on a lost, damaged or failed device to be restored to a replacement device should it be necessary. For the most part, iCloud storage does not provide “archive” storage of files and data - you’ll need to use a different cloud service or storage device for archiving data that you don’t wish to keep on your iPad or iPhone.