As will says; vCarving is the best bet for high-precision. The fact that CarbideCreate can do it, and for free, is amazing.
After that you’re talking about doing pocketing operations with small endmills. How small depends on the text size. If you’re making signage with letters in the ~3" range, then a 1/8" end mill will cut to a reasonable degree of accuracy, with proper font selection. You could also go down to a 1/16" (.0625") end mill and do contour-on operations to trace the exterior lines of the fonts.
They are very sharp and really inexpensive. They work great as @WillAdams suggested above for my very small engraving, for larger engraving I have the 90 degree ones that Carbide3D sells as well as some small 1/8" 90 degree bits from same seller as above on EBay.
I used the ones above for these Christmas ornaments recently:
If you want any small text with detail you have to do V carves, I’ve done some larger stuff with small 1/16" (0.0625") flat end mills, but it was very basic text. Remember that if the angle is more acute it will have to go deeper for a given letter width, that’s why you wouldn’t want to use a 45 degree V bit to do 3" tall letters, …unless you use software that can limit the depth of cut (“Flat Depth” in some softwares).