How can I remove this list of the module K2 Users, ordering choice?
With this template it is set to h3, but I rather have it removed completely from the K2 Users listing I have.
Ordering settings: Latest


Ordering settings: Alphabetical


Thanks

I am not sure I understand you completely.
Are these headers (the sorting option) visible on the front-end?

No this is right of the Item Title, showing it next to each item.
"Programma Items" is the module header of K2 Users.

No this is right of the Item Title, showing it next to each item.

So they are visible. This means that it is a template issue.
You need to address this issue to the template's developers since they built these overrides.