Here you can edit global application settings by clicking on the corresponding value, most importantly, when using the TagTool as a keyboard emulator you should ensure that "Start as Administrator" is set to "Yes", this ensures that the TagTool can insert text to another program.
You can also chose whether to start TagTool when Windows starts and whether or not this should be minimised upon loading.
You have the option to change the threshold for the Active Tag Battery Warning, however 2.4 is the recommended value for monitoring of Active Transponders.