If this information you want to show is common to every page of the application, then you may want to add it to the layout. In case you're using Atlas, search for something like Atlas_TopBar. It is usually a good practice to not edit the marketplace module directly, but a copy instead.
In the Atlas_TopBar snippet, you can see the app icon, navigation bar and language selection. You may add a dataview to show the User's name and profile picture.
Even if the layout you're using is not Atlas, the process should be similar.
To show the user's profile picture, please see this forum question:
https://community.mendix.com/link/space/app-development/questions/133256