How to create a new iCloud account
iPhone in Business and Education
[Re-Titled by Moderator]
What you are calling an iCloud account is an Apple ID.
Depending in how it was created, an Apple ID has some amount of iCloud storage included, with up to 5 GB free.
there are various ways to create new Apple ID: How to create a new Apple ID - Apple Support
If you are attempting to create an Apple ID on a device that has already created its quota, you will need to use one of the other paths available to create a new Apple ID.