There are a number of CRM/Software with which Pepipost can be integrated, following links will guide you to the configuration/settings of the same
- WordPress : WP-MAIL-SMTP
Pepipost supports SMTP integrations in some forums as well :
Pepipost also supports SMTP integration on mail servers:
If you have any other CRM/software and it has a option to add SMTP details then you can follow this link.