When you start working with a personal assistant, you'll find that communication matters. After all, this is someone you're sharing your important files and documents with: coming up with a simple way to exchange information may make it easier to get things done. It may seem like an old-school method, but color-coding could actually help you do this, and bring other benefits as well.
Last year, Fast Company went into the details of how color-coding can bring some structure to your notes. One of the points this piece brought up seems especially relevant when you have assistants. Making notes in different colors gives you a chance to give credit to the correct person when multiple people are involved in a project.
If you and an assistant are making multiple passes on something, you can each use different colors to distinguish who is adding what. Color-coding can also help prioritize certain tasks and "action items" over others, which can be extremely useful on a long list. Neither you nor your assistant should have to dig through line after line of information when there's something pending that could stand out.
While this piece specifically applies to physical, pencil-and-paper notes, it's not hard to see how this could translate into the digital world. You can give your assistant a chance to get more work done, for example, if you go through your email inbox and highlight the most important threads. Don't know how to do this in the latest office programs? It's still a good idea to bring it up with a new assistant to start the relationship off strong.