How to create a business email account in 5 minutes?

I recently signed up for the Hostinger and my email won’t send. However I can receive mail. It’s asking to configure email. Would be nice if you did a demonstration vid on configuring. I’m using Apple

If you already bought the domain, why do you still need to pay an annual fee?
How is a domain actually stored or owned then? Can you do a video about it if you haven't alreadt?

This website seems to be untrustworthy. I’ve selected every plan they offer. Each one has a price for what it is per month. But when I try to checkout the only option for any of the plans is to pay for 1-2 years upfront. Not a subscription. The website says 24 hour support. But I can’t get in contact with a single person for the last 2 hours.

How many domains does Hostinger allow me to have if I just bought the plan? Does Hostinger allow me to change domain names?

You’re the man Thanks