How to make sure that emails from the site do not go to spam?

Question

Notifications

Good afternoon!
From my site, people receive messages, for example, about receiving new comments, replies. Sometimes people do not return, as most likely the letters end up in spam! not all of course, but they leave.
Tell me where and where to dig in order to set it all up so that it does not go into spam?
There are also plans to make up and apply a new design of mail notifications. To be neat and beautiful

Answer 1

Here is what mail.ru advises - this is

Answer 2

Formatting letters does not affect anything.
From Yandex:

If the mailing list is identified by the system as spam, first of all we recommend that you make sure that it complies with the rules and requirements of our company. Detailed conditions are published on the pages https://yandex.ru/support/mail/spam/honest-mailers.xml and https://yandex.ru/legal/rules/ .

Answer 3

1) Place mail on pdd.yandex.ru
2) Create a mailbox for WordPress
3) Install and configure https://ru.wordpress.org/plugins/easy-wp-smtp/ to send mail through a mailbox on Yandex
4) PROFIT!