It keep on saying that iCloud is full

Hi newton160,

Welcome to the Apple Community.

Before you delete anything to free up storage in iCloud:

if you want to:

It is really a good idea to back up or save all, or at least your favourite or precious, files, photos, videos etc.

Eg: to a flash drive or portable / external drive:

____________________________________________________________________________

Archive or make copies of the information you're storing in iCloud:  (includes contacts, etc)

https://support.apple.com/en-au/guide/icloud/mm532b789536/icloud

Apple Support have other articles online to help you:

Transfer photos and videos from your iPhone, 

https://support.apple.com/en-us/HT205856

Or

in iOS14

Connect external storage devices to iPhone:

Attach the USB drive or SD card reader to the charging port on your iPhone using a compatible connector or adapter.

https://support.apple.com/en-au/guide/iphone/iph95baac91f/ios

_________________________________________________________________________

Manage your iCloud storage:

https://support.apple.com/en-au/HT204247

For more detailed info on deleting files:

Delete files in iCloud Drive on iCloud

https://support.apple.com/en-au/guide/icloud/mm3b7fcd0c10/icloud

Recover deleted files on iCloud

https://support.apple.com/en-au/guide/icloud/mmae56ea1ca5/icloud

Permanently remove deleted files on iCloud

https://support.apple.com/en-au/guide/icloud/mm9cf51c51f4/icloud

Delete shared files or folders in iCloud Drive on iCloud

https://support.apple.com/en-au/guide/icloud/mm532b789536/icloud

Hope this helps you :)