I entered my iCloud password correctly but this web shows me password or Apple ID is incorrect what can I do for open my iCloud

You might be using an Apple ID and password ( that would be active ) to access this website and the credential were correct so you signed in the account .

If you enter incorrect credentials like Apple ID address and password it won't accept .

For the non active Apple ID see some links https://iforgot.apple.com/appleid#!&section=appleid

https://support.apple.com/en-in/HT201354

https://support.apple.com/en-us/HT201487

To downloads photos turn on photo box from the Mac / iPhone what ever you are using https://support.apple.com/en-in/HT204264

https://support.apple.com/en-in/guide/photos/pht5156cc968/4.0/mac/10.14

https://support.apple.com/guide/iphone/use-icloud-photos-iph961b96c4d/ios