I bought new iphone but its locked by icloud,what i have to do

https://support.apple.com/en-us/HT201441

If you're the iPhone's original owner, supply Apple with its purchase receipt. If not, ask the person who set the lock to remove it or give you a refund.

If it's locked to your Apple ID, you should just be able to activate it; if you can't log into it, you're likely better off addressing this than having the lock bypassed.

(184566)