Yandex.Mail for Domain is a free service for setting up email on your domain.
You can create mailboxes like "username@<your domain>.tld" and your mailbox users can use the Yandex.Mail web interface with all of its advantages, including the spam filter, automatic virus scanning, chat, and other features.
Mail for Domain users can also log in to other Yandex services, such as Yandex.Disk or Yandex.Music. They can just enter their email address as the username.
For a single domain, you can register up to 1000 mailboxes, which you can use yourself or give out to other users. You can manage your domain in the web interface or via the API.
Mail for Domain users can't access:
Yandex Advertising Network
money transfers to artists on Yandex.Music
subscription payment in the Yandex.Music mobile app