why i can’t connect my apple id to i cloud?

You are sign in here .  .  .  with your Apple ID & Password (?).

Your Apple ID is the personal account you use with all Apple products and services. It includes the email address and password you use to sign in, as well as the contact, payment, and security details that you use with Apple.

You can’t merge multiple Apple ID accounts.

See -> If you can't connect or sign in to iCloud

If you can't connect or sign in to iCloud - Apple Support

Hi there!

Apart from the steps in this article

If you can't connect or sign in to iCloud - Apple Support

You may want to disable or uninstall your VPN or security software if you have one. Sometimes, they can affect how you comnect to Apple's servers.

If you can sign in your Apple ID on another Apple device or at appleid.apple.com, most likely it's a device specific issue.