Many site owners face the spam mail problem for using the WordPress default PHP mail function(). There may be some restrictions when it comes to mail service: sometimes emails are not delivered, sites cross the limit of outgoing mail. Bit SMTP plugin allows you to authenticate the mail service of your site by configuring the SMTP server of your desired mail service. SMTP is a protocol that helps your WordPress site make its email deliverability more easygoing & reliable. By enabling this feature, you can send mail from your site to your recipients via your preferred mail server.
At first, you have to open an account on your desired hosting provider (e.g.: MailGun, Gmail, Yahoo, Hotmail, Zoho mail). By opening an account, you are authenticating your WordPress site. They will provide you the necessary credentials (e.g., Encryption type, SMTP port ). You have to put this information when configuring SMTP on your site. Once your site is authenticated, you can send mail through your preferred SMTP server. All the email validation work will be done on your specified SMTP server.