Installing "Imap-SSL / Pop3-SSL"

[serverblend]

I am trying to follow this guide: https://docs.whmcs.com/Email_Piping:_Google_Apps

I have done everything except this part:
> Please ensure that Imap-SSL/Pop3-SSL in the PHP installation on the server. Such a change (if needed) will usually require the hosting provider or system administrator to do this. The reason for enabling this is because GSuite services will only accept secured connections.

I am desperately trying to understand what this actually means. I know what imap, pop3, SSL and PHP are. I understand that, _somehow_, they need to be installed and enabled on the server. I have googled this for probably hours now. This guide is severely lacking in specific details here. I've done everything I can find a guide for on enabling this and it is not working.

What does this mean? What **exactly** do I need to install, and **how** do I set it up?

[serverblend]

For anyone else hitting this issue, I was able to get this to work by adding 2-factor authentication to the account, and then creating an app password. Using the normal login password was not working, however the app password seems to work.