Website Call Conversions (WCC) allows advertisers to measure and attribute conversions from calls generated by visitors clicking on ads and calling numbers on websites. It extends existing call tracking by attributing calls from websites to ad campaigns. WCC dynamically generates unique forwarding numbers to replace website numbers if the user clicked an ad in the last 30 days. Setting it up involves enabling call extensions, creating a conversion tag, adding the tag to pages with phone numbers, and creating phone number snippets to replace numbers with forwarding numbers. Verification involves clicking an ad to visit the site and check if the number was replaced.