If you have SingleApplication version (for example, ReplaceMagic.Word) then you will see only extension of documents for which you have license:
and only this extension(s) will be in File Types Selection form.
In case that you have one of Bundle versions (ReplaceMagic.Office or ReplaceMagic.Total) you will see all supported extensions like
and in File Types Selection you will have them also:
By double-clicking on document type you can move it from one side to the other or you can use buttons (Move right, Move left, Move All Right, Move All Left).
Also you can do multi-selection using Shift+Range of extension or Ctrl + single clicks.
Everything what is in right-hand list will be used for scanning documents.