if your sync folder is taking too much online space, move files outside the sync folder to else where
if other creative cloud files are taking too much room, but you want to preserve them, download them from your cc web folders and save them locally (not in your sync folder).
then delete whatever you don't want on your cc web folders.
here's basic info: https://helpx.adobe.com/creative-cloud/help/about-cloud-documents.html
then for more info go here and check the beginner (if applicable) tutorials for cc useage and then advanced, https://helpx.adobe.com/creative-cloud/tutorials-explore.html
In order to free up storage, you have to disable the photoshop presets feature as described here (chose NO when asked to keep the data in the cloud): https://helpx.adobe.com/ie/photoshop/using/sync-presets.html
then go to your cc web site by opening cc desktop app>clicking cloud icon>cc web empty all 8 folders (4 in your files, 2 in shared with you, 1 in shared with you, 1 in deleted).
note: if you delete from your sync folder, your local files will be deleted, too. this is the only folder that affects your locally stored files.
click the lightroom link at bottom left of your cc web page and delete files from there. lastly, recheck your deleted folder and delete whatever is there.