Printing 3D letters in any font?
I think @Trish answered your question more specifically, but an alternate route (that I think its simpler assuming you don't mind the learning curve) is using Blender.
Rather than creating an svg in a different software and having to go from something like photoshop to inkscape to tinkercad to your printer software...  Blender could do most of that in one step, and its free.
In Blender, add text:

Hit tab to go into &quot;Edit&quot; mode and in edit mode you can simply backspace and type whatever you want.

In the &quot;Font&quot; menu, you can choose from any font on your computer.


And you can make it &quot;3D&quot; by extruding it:

When it looks good and you're ready to print it, make sure to convert it to a mesh, then export as .stl for your printing software. (Cura/Slic3r/etc.)