This appears to be coming from the productivity app Things 3. You may have this in your login items (Settings → Users & Groups → User → Login Items). Disable it there to prevent it from automatically starting.
Their support site has a great deal of info on how to use the product, but I was unable to find anything on preferences/settings. There should ...
You can use the QLStephen plugin as mentioned but you will need to edit it as described in the project's issue tracker: https://github.com/whomwah/qlstephen/issues/23#issuecomment-21769063
Basically: open the .../QLStephen.qlgenerator/Contents/Info.plist file in a text editor, and add the UTI public.yaml to the key LSItemContentTypes. Then run qlmanage -r ...
Here’s a shortcut I’ve made that does this: Apply Conversions.
Given input, either from
a note (tap the Share button in the upper-right)
selected text in any app (tap Share from the selection menu)
the current clipboard (run the shortcut from the app or the widget)
the output will be produced. See the example below:
When importing the shortcut from the ...