Transferring files between two Apple ID accounts I am currently in a joint Apple ID account and I'd like to transfer the files and data in my iPhone to a new individual account I created. My iCloud storage is completely full up on the joint account. 

Q: Is there a way to transfer my data onto my Mac or a new iCloud server so I can put them onto my new Apple ID account?
I guess each Apple ID has a dedicated iCloud account.  Login and logout with each individual Apple ID from your MAC and use terminal to access all the documents belong to each Apple ID that are stored in the iCloud . After you access the iCloud account you can move files from the iCloud account to your personal Desktop or anywhere you want.

Try the following Terminal commands:

cd ~/Library/Mobile\ Documents/com~apple~CloudDocs
mv fileName.ext folderName