If you want to enable the auto-configuration in your e-mail clients (Outlook, Thunderbird) in order to benefit from the auto-configuration assistants / auto-discovery offered by local programs. Then, you can do so by referring to an autodiscover/autoconfig XML file, and other well-known URLs that are available on our web server, in your custom domain (e.g., mydomain.com) DNS records.

SRV records:

Service: _autodiscover
Protocol: _tcp
Hostname: _autodiscover._tcp.example.com (replace example.com with your domain name)
TTL: 600 (or leave it to auto)
Target/Destination: mailfence.com; Priority: 0; Weight: 0

Set _autodiscover._tcp.mydomain.com as a SRV to mailfence.com: (for SMTP, IMAP, POP and Exchange ActiveSync protocol service discovery)

_autodiscover._tcp.mydomain.com. 600  IN  SRV 0 0 443 mailfence.com.

Set _caldavs._tcp.mydomain.com as a SRV to mailfence.com: (for CalDAV protocol service discovery)

_caldavs._tcp.mydomain.com. 600  IN  SRV  0 0 443 mailfence.com.

Set _carddavs._tcp.mydomain.com as a SRV to mailfence.com: (for CardDAV protocol service discovery)

_carddavs._tcp.mydomain.com. 600 IN  SRV  0 0 443 mailfence.com.

CNAME record:

Hostname: autoconfig.example.com (replace example.com with your domain name)
TTL: 600 (or leave it to auto)
Target/Destination: mailfence.com

Set autoconfig.mydomain.com as a CNAME to mailfence.com: (for SMTP, IMAP and POP protocol service discovery)

autoconfig.mydomain.com. 600    IN  CNAME   mailfence.com.

Note: Clients that cannot utilize DNS SRV records, will go for CNAME record. Please be aware that this will lead to a known SSL warning in some clients (e.g., Outlook).