[HNW] embroidered stomacher and new projekt

[MLF]

I have a dummy question since I'm new to embroidery beyond 
cross-stitching/backstitching.  What if I wish to put blackwork or some 
other stitching onto a garment, say at the hem or collar or cuffs.  Is 
the common method to embroider the piece of fabric before making it into 
the garment?  Or is it simply common to work the design onto the 
finished garment without any kind of framing to hold tension on the cloth?

Much thanks!
-m

-- 
Thig crioch air an saoghal,
ach mairidh gaol is ceòl.