My iphone storage is full, i have 2T on my cloud storage, the photos are there and yet the iphone storage is mostly photos. Helps!

Settings > Photos

Do you have optimize photos selected? That will help to reduce the size of the library on your device.

Then you'll need to begin deleting content from your device to free up space. Anything that you delete that syncs with iCloud will delete everywhere so be sure to backup or move the most important data.

You are using it. But, iCloud is not an extension of your storage or offline storage; it is primarily a synchronization service. You may not need 2 TB of storage depending on what you are syncing and the size of your device. For example, I have 2 TB but I use a Mac, iPhone, and iPad and also sync family iPhones to the account.

You can subscribe to online storage sites (Google Drive, DropBox, etc.) to which you can offload your items. But, you'll lose the automatic syncing enabled with iCloud. You can also offload your documents and data to an external hard drive or computer. Of course, you'll then want to ensure that you are backing up all of your data too.