Support, what Apollo enrichment I have to use to find people from a company list

You can't unless you want to pay a lot of money.

Find Job Titles of People at Company (something like that) will get you your people by job title from companies, it's 1 Apollo credit per successful API call.

Also, it won't return an email (weird)

If you want to use official apollo API through HTTP API in Clay, you could but that would be 1 credit per person, even if it doesn't return an email

Using the Apollo interface is the best way to go about it due to the limits of the Apollo API

Clay integration is cheaper than Apollo API, if you don't care about emails. If you want emails, it makes sense to do Apollo API - but above all else, using the Apollo App directly only charges a credit per successful email found and gives you people info for free. Way better than all options via API. I am talking to Apollo team to work out a private deal, if I get something, I'll let you know!