Question about custom page.php

Hello!

I’m using WordPress for the first time and I know PHP very well.
And now my question, can I create a custom page.php where the user can type text to a textbox and press sumbit and it would be uploaded to database?

I would the same system as the blog-system where I can as an admin view latest post from the users at admin-panel, edit them and so on ??

What do I need to look at? Also, I need a comment system for each entry.

This custom page is like the blog-function, but instead of the admin, the user is creating entries.