This will not affect RootsMagic 8. As others have pointed out,1) The new ARM-based Macs won’t even be available until the end of the year,2) Intel-based Macs will be available and usable for years to come, so the transition will be gradual, and3) Apple’s “Rosetta 2” emulation layer ensures that all your existing 64-bit Mac software will run fine on the new Macs.
As I started this diversion, I thought I would expand a little on what Bob has correctly stated in a hope to close this off.
Having followed the link provided by TomH to the cross-platform development tool being used for RM8, the last stage of packaging the Mac version for distribution involves the use of an Apple provided development tool, Xcode Running on a Mac. When using that tool, one specifies the target environment where the program is to execute - the tool is used generate/package iOS apps as well as Mac applications.
When generating Mac programs, it has been creating programs for the Intel architecture only. However, the latest version can generate programs for Intel, ARM, or “Universal”, the latter including code that can run on both Intel or ARM (Apple Silicon). By default, it will now generate Universal code, but can be set to generate Intel only or ARM only code. In the RM8 case, it may need some tweaking of the output from the development tool to successfully generate a Universal version that will run on ARM. These tweaks, which are expected to be minor, would be up to the developer of that tool, not RM development.
If RM8 for Mac isn’t initially shipped as a Universal program, then as Bob says it will still run on ARM by automatically invoking Rosetta2. This is more a translation tool rather than emulation or dynamic interpretation, and this usually occurs once at program installation time rather than at every program load. It involves scanning the Intel machine code and generating appropriate ARM code.
I hope that helps rather than muddying the water further.