Email hosting

Your domain provider will often provide email services to go with your domain. Hover do this for instance.

I have a VM in Azure running webmin/virtualmin where I host my old clients emails. You have to open a support ticket with them now, as they block any email sending by default.

Otherwise I use Microsoft to host my emails on their exchange servers. It's a monthly fee, but I never have to worry about it. For my new clients I'm insisting they run their emails through gsuite or Microsoft, as it's just one less headache. Any transactional email from any website is then sent through mailgun

@morganc3 Pro tip, if you want to do this for free... transfer your domains to Google Domains and use email aliases.

Amazing trick: https://support.google.com/domains/answer/9437157

I've been doing this for smaller apps and it works great.

Otherwise pay for a Hover or Gmail G Suite account... if this is just for transactional email, consider using AWS SES.

Also, you can just use Gmail too. Just allow third-party sending in the security settings, enable IMAP/POP and plug smtp.gmail.com:465 into your apps.

handling email issues (email lost, blacklisted, attack, virus, performance, etc....) are not an easy task, it's quite time consuming... unless you have plenty of resources, otherwise, suggest you go to subscribe any plan from the hosting provider that suitable to your requirements.

For reliability and security and feature rich, i personally recommend Microsoft and Google...