I'm looking to crate a custom font. The font has 2 colours - a coloured fill and a different coloured hard edge shadow. Is this possible and how?
Font files (well, most types of font files) don't contain any color information...which makes sense as the designer is the one that has to choose the color.
For creating fonts that ultimately will be nice to have rendered in multiple colors, the typical solution is to separate the parts you want as different colors and put them into separate glyphs. The designer can then layer the type using the different glyphs in their editing software.
This is often called a 'chromatic' font. Many examples:
Here's one of those examples showing the multiple glyphs that can be combined to make a multi-colored letterform: