Free version very limited. Just one Delivery services free

Hi,

all delivery services provide the standard SMTP way to send emails, you just need to install an SMTP plugin (WP Mail SMTP, Fluent SMTP, …) and connect the blog with the delivery service of your choice. Newsletter uses WP to send emails and the SMTP plugins deliver them via the service you connected.

The Newsletter plugin does not provide direct connection with delivery services they can be used as explained above or using the addons (but it’s not strictly required to use those services).