100 GB storage is included with your Creative Cloud license, you can also find this information on the product page. However, your Adobe account could show a different storage capacity. We understand that this is confusing, but unfortunately it is not possible to change this short term. The 100 GB we communicate on our product page is leading in this.
On this page on the Adobe website you can check how much storage you currently have, what counts as Adobe Creative Cloud storage and how to remove files to create space.
We recommend downloading the files you want to keep and then storing them in a location of your choice (e.g. an external hard drive).
Unfortunately, it is not (yet) possible to purchase extra storage. You can find more information on this Adobe page.