Please specify the product/ subscription which you want to upgrade?
What we have is the product Creative Cloude membership, for 1 user
You can sign up for a 2nd Creative Cloud Individual membership using a different Adobe ID for the 2nd user. You may also wish to consider Creative Cloud for Teams.
As correctly suggested by Beverley Gray, you will have to subscribe to unique Adobe ID for different subscriptions.
Please refer to the below mentioned link under " Purchasing and availability- Can I buy more than one membership to an individual offering of Creative Cloud":