FB ads, what is the most effective target of the ad. in a sense of calls through the website

Hey, can somebody help me out, I have a client he has a website, you can not buy directly from the website and can’t put a product to the cart. You can only enter the website, send the inquiry or make a phone call through the website. What would be the most effective type of ad on fb that will make people send inquiries or call through the website? and 2nd questions do I need to put a pixel in this case, and where?