special keys

In my music I need keys to specify the note to play, but I also need special keys to indicate the movement (or gesture) to achieve. Especially with bow instruments, where I sometimes need to show the place of the finger on the fret.
In Dorico, I need a graphic program in ordre to draw my own key symbols and transfer them in the “key” function on right of the writing page.
Is it possible?

In the music Symbol editor under engrave mode you can just replace the glyph of any unneeded key with your new one.
If you don’t need the tenor clef in this piece, just replace it with your own, for example

Thank you.
Unfortunately, I cannot understand how to draw my own “glyph” . I found how to import files, but there must be a way to draw my own glyph, no?

No, you can import (vector) graphics, use the glyphs from any font or (if I remember correctly) chose a text as glyph and add it.

You can use any graphics editor to create graphics to import into Dorico. I would personally recommend Affinity Designer, but lots of other similar applications are available, including free ones like Inkscape.