I was doing a few custom tags for my outdoor post box due to some local German law requirements. This is a simple tag that you can adjust to your needs, just take a Freecad file and edit.

Note, Freecad may be slow in recomputing the full model, so please consider disabling auto-recompute by right click on "YourTextTag" (model file name) and selecting "Skip recomputes", after the changes click on "Body" and select "Recompute object".

For the record: 1mm canvas height and 1.5mm text pad height. I find 1.5mm text pad height optimal for then coloring with a permanent marker.