I am not able to find my new lead, which is supposed to be there.
i used this link -https://webto.salesforce.com/servlet/servlet.WebToLead?encoding=UTF-8" method="POST"&oid00D4W000006kcK0&first_name=Bingh

Sorry you're stuck but there's almost always a pretty easy fix! Do NOT try to start all over again, uninstall Max's Pitch Package, etc. That can make it worse. There's a 95% chance the same snag/fix is listed & answered in the Help FAQ. But if you can't find it there, post your problem here.
Make sure you post in the right category below & be sure to include a screencap showing the issue!
You left out the equals sign between "oid" and your ID number
Thankyou so much
it worked now.
Sure, np! Happy to help.