When does the User IP connect to contact?

Your software
My Mautic version is: 2.15
My PHP version is: 7.2

Your problem
My problem is:
I do not know how to connect user IP to the contact.

I’ve been doing some tests with myself as user and even though it properly sends emails and it shows my IP as having used the website, it doesn’t connect both data points.

How can I connect IP of website visitor to the contact?

I thought this was going to happen naturally when an email was sent.