Hello swapna52,
Thank you for using Apple Support Communities. If you would like to delete photos on iCloud as well as all your Apple devices, first make sure iCloud photos is turned on when you navigate to: Settings > [Your Name] > iCloud > Photos. By turning this option on, you are syncing your photos with iCloud and all your Apple devices as long as you're signed in with the same Apple ID on your devices. Then follow these steps:
Delete photos in iCloud Photos
iCloud Photos uses your iCloud storage to keep all of your photos and videos up to date across your devices. You can make more space in iCloud when you delete photos and videos that you no longer need from the Photos app on any of your devices.
Before you delete anything, make sure that you back up the photos and videos that you still want. When you use iCloud Photos and delete a photo or video on one device, it's also deleted on all other devices where you're signed in with the same Apple ID.
Use the steps below to delete photos and videos from your iCloud Photos. If you don't use iCloud Photos, you can delete photos from your Camera Roll instead.
If you are part of an iCloud Shared Photo Library, photos added to the Shared Library only count towards the storage of the person who created the Shared Library. To delete items that count towards your iCloud storage, make sure that you're viewing your Personal Library.
Manage your iCloud storage
You can also, follow the recommendations in the link above to manage your iCloud storage and free up space.
Let us know if you have any questions. Kind regards.