how can i remove my iwatch from Activation lock

Did you read the information in the Related Article? You need the Apple ID and password used to activate it. About Activation Lock on your Apple Watch - Apple Support

And if you are not the original owner then;

The person that you bought/got this watch from needs to follow all the steps on this page;

Remove the Activation Lock so that the buyer can use it.

If they can't or won't then get your money back or recycle the watch and mark it down as a bad experience.