Choose http or https during the manual installation of WordPress and the database

Quote Originally published by theforamyst
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When you manually install WordPress, somewhere during the process, it asks you to select the weather in which your site uses http or https. Why is this? Does matters? How will your choice be translated into changes / a different use of, for example, your database?
When I installed WP, ​​I chose http bc at that time I did not have SSL yet. Then I created a few pages, posts and categories. The URLs of these started w / http.
Then, a while later, I installed the SSL certificate in that domain name and, since then, the pages, the publications and the categories that I created, its URLs, started with https. I can not remember if I had also changed http to https in the WP Dashboard configuration.
What makes the choice for http or https (during the installation of WP) is to determine the weather or not to place http or https in front of URLs of pages, publications and categories that it will create since then?
So, where does WP store these URLs (are they called "links"?). In the database? At what table (s)? How does this work?