There are several ways to achieve this. The easiest way is to use out of the box Mendix functionality. Once you create a new project you will have a module called administration. Add ‘Account_Overview’ page to your project navigation and than run the project. Open the app in browser and go to account overview page which you added to navigation to create / manage user accounts (if project security is turned on than login as administrator e.g. MxAdmin). To test from your localhost go to yourappurl/login.html e.g. http://localhost:8080/login.html and enter the new log in credentials.
If you have not already done so than I will recommend you to go through learning paths on Mendix academy.
Hope this helps!