Notes from a trusted customer who at first tried unsuccessfully to import fonts into TurboCAD.
I searched for a font converter, thinking I would convert to SHX files. The answer is my missing fonts were OTF type. They install in Windows 10 but TurboCAD does not recognise them. TurboCAD likes TTF fonts. Convertio does the trick, it converts files. My OTFs are now TTFs, and TurboCAD is quite happy.
See Link https://convertio.co/font-converter/
It says ‘FREE’, but the limit is 10 converts per day, then it tries to smack you with buying a licence.