i dont remember icloud passcode. how to recover it??

You need a computer.

Read this Apple article: If you forgot your iPhone passcode

https://support.apple.com/en-us/HT204306

Note that you can't actually recorver the code as it's stored only on the device (it has nothing to do with iCloud). The instructions in the page linked to above will erase the phone - there is no other way to proceed. Hopefully you can retore the contents from a backup.