How to send a large number of emails?

Question

PHP

Users indicate their email during registration, receive a password to it. On the same email they will receive notifications about important events for them. Expected 10-20 thousand messages per day.
The goal is for everyone to get their letters. I will survive if they get into spam, the main thing is that they are guaranteed to reach the addressees.
Before that, to send letters, I managed with the usual php mail (), but as I understand it, this will not work for sending a large number of messages.
on the page with the mail() function in php.su, it is suggested to use pear Mail, Mail_Queue and Mail_Mime - as I understand it, this is something like additional programs for the server. you just need to install them and continue to use the usual mail(), and with their help everything will be processed by itself?
On the forums they write about smtp - this, as I understand it, is a connection to another server and sending mail through it - that is, before sending mail in the script, register a connection to that server and use a slightly different command to send it?
And very often they write about postfix - but it seems to be also a program like pear
In general, as it has probably become obvious in my question, I don’t understand anything at all. Everywhere they write about setting up all this, and not what and why you need it.
Please poke me with my nose what and where to read or write what and how I can use to solve my problem.
Thank you.

Answer 1

You need to use mailing services.
For example, www.mailgun.com
They differ from simple SMTP in that mailers know that this is a mass mailing, and your letter is almost guaranteed not to fall into spam.

Answer 2

Buy 5-10 nodes, set up smtp on them, queue all letters, select from the queue and send them through your nodes .. the more nodes, the faster the mailing will be. etc.

Answer 3

www.mailwizz.com

Answer 4

mailgun/mandrill

Answer 5

You can use our service - mailhandler.ru. We give 10,000 email messages for free so you can try our service and see if we are right for you or not. We have both an API for transactional emails and an interface for bulk emails (with a constructor and HTML editor). Plus, we provide email tracking capabilities, embeddable opt-in forms for your website, and more.