Cloudflare itself does not provide these services, so I can suggest two solutions:
Running your own server: While you can still read guides for on setting up your own personal mail server, it requires you to invest a lot of time into setting up and maintaining the server yourself. You would also have an uphill battle if you’re sending e-mail from a residential IP address, or even a VPS IP address since these are very often given super low e-mail reputation scores.
Hosted: These days, I’d recommend a premium domain e-mail host like Google Workspace (gmail), Office 365 (Microsoft), or Proton Mail. You might be able to purchase email from your current website provider, but these providers often have security, integrity, and availability issues so using one of the big providers listed above is usually a better choice.