Your WordPress site sends emails to notify you of new user registration, lost password reset, automatic updates, and even notifications from your contact forms. By default, WordPress uses the PHP mail function to send out email notifications. However, this function does not work as expected due to a number of reasons. Most WordPress hosting companies restrict usage of this function to prevent abuse and spam.
Spam filters on popular email service providers check incoming emails to monitor if they are sent from the authentic mail server (SMTP Server). Default WordPress emails fail this check. And sometimes may not even make it to the spam folder. SMTP (Simple Mail Transfer Protocol) Server is the industry standard for sending emails. Unlike PHP mail function, SMTP uses proper authentication which increases email deliverability.
Email provides SMTP service that you can use to send out emails from your WordPress site. If you just want to send notification emails to users on your site, SMTP server is the best option.
However, if you are planning on sending newsletter emails using WordPress, then you should use a mass emailing service provider, like Mailcot.
You can use your free Gmail account to send out WordPress emails. However, for better deliverability, we recommend using paid SMTP Service.
SMTP Service requires you to add MX records to your domain name which means that your emails will appear to be coming from your own domain name boosting authenticity and ensuring better deliverability.