i have been trying to clean icloud storage

5 GB of iCloud storage is indeed free, and that's often enough to make a daily backup of the phone. But having lots of data, especially having lots of pictures, can pretty quickly get you way beyond what 5 GB can do.

For many people, $1 / month to get ten times that storage is not so bad, and it relieves a lot of potential headaches. I do wish that for $1 I could get ten times the storage at home in my garage! In fact, I spend $3/month for 200GB, and that works well for me. Those links that TheLittles provided can help if you want to store your data off your phone and also off iCloud.

If you turn on Optimize Storage in iCloud Photos, then the iPhone may use only 10% as much storage on the phone by keeping large originals at iCloud.

You don't say what you use at iCloud. iCloud Photos, iCloud Drive, Mobile Backup, and other services there are separate things, and they involve separate methods for management. You may need to examine why you use iCloud at all.

See this:

Understanding iCloud Photos - Apple Community

and this:

Understanding iCloud Drive - Apple Community

"i have been trying to clean icloud storage : clean icloud storage having a problem can’t clean iCloud Storage i thought it was free why do i have to pay more storage"

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Making iCloud Space:

A. Export All of iCloud Drive:

Export all of iCloud Drive to an external hard drive, and verify you can access it, still. Then, trash what is in iCloud Drive. Use my User Tip: Getting a Quick and Direct "iCloud Drive-to-External Hard Drive" Download - User Tip

B. Download the Rest of iCloud:

Refer tote Apple Support Link: Archive or Make Copies of the Information you Store in iCloud - Apple Support