Hi Lisa. I don’t mean this to sound like a ‘flip answer’ because it’s not intended that way, but I’d say the “best software” for your purposes is whatever software truly serves YOUR purposes. I don’t believe in a “one-size fits all” in training nor in our business operations. You may find that one trainer LOVES a particular program for whatever reason and another hates it – so “best” is truly relative.
I use a simple Excel program to track my clients sessions and payments and it works well for me. But, any program that does or can be made to, track these two components can work.
I hope that this helps.