I find having a landing page with a strong value proposition, form, and phone number at above the fold tends to work well. Like, 70% of the time. 20% of the time the form at the bottom works best, and 10% of the time having the form on the contact page with a link from the landing page works best.
I’ve also noticed that many times having no value propositions or forms tends to convert best.
Sometimes, my crappy pages with no substantive content or easy way to convert tend to perform best.
I’ve got one that doesn’t even have a header or navigation or business name. The ad just links to a form and basically says “sign up or leave.”
Test. Then test some more. Then do most testing.