如何根据帐户的用户名添加URL

How do I supposed to create a url based on the username of the user?
Can someone help me with the codes and the .htaccess configuration?

users.com/usernamehere

If you want to view it on Github
If you want to view it on a live website

Info
If my user wants to view his page, he's gonna go to "users.com/hisusername". The link is gonna get his username and displays information about his account, and the .htaccess gonna have the re-write rule (I guess?). Can someone help me with the code?

Suggestion
I've saw this in some tutorials but I can't follow them, so if the page have the tag of "?username=usernamehere", the user is gonna be redirected on the "usernamehere" page.
Example: The user is on "users.com/profile.php?username=Stackoverflow" and the user is gonna be redirected to: "users.com/users/Stackoverflow". Any chance of this gonna happen? Thanks and have a good day :)

The user is on users.com/profile.php?username=Stackoverflow and the user is gonna be redirected to: users.com/users/Stackoverflow. Any chance of this gonna happen?

Note: Although this quote suggests the opposite, the answer below assumes that you want the user to enter users.com/users/Stackoverflow in the URL bar.

Place a file called .htaccess in your website's document root (the highest directory that contains your website files, typically called public_html or www) Add the following rules

RewriteEngine on
RewriteBase /

RedirectRule ^users/(.*)  /profile.php?username=$1  [END,NC]

The NC flag makes the comparison case-insensitive. Meaning that users/Stack and USERS/Stack will both be redirected. Remove it if you want a case-sensitive comparison

The END flag tells the server to stop looking for more redirect rules. Basically it ensures that /profile.php?username=... be the final destination of that request.

addendum

If you really want to redirect customers in the opposite directions, use this rule instead

RedirectRule ^profile.php?.*username=([^&$]+)  /users/$1  [END,NC]

This will probably cause you problems though if the path /users/name is not a real file