Currently in SimplePractice you have the option to create individual or couples sessions. In the future we'll be adding more features for group, family and couples sessions. These are complex features that we have been designing and building for some time. To fully integrate these features into the software takes time and we will be proud to release these so they are both useful and simple at the same time. Our goal with every feature we develop is to maintain simplicity in the workflows for billing, scheduling and documentation.
There are however a large number of current SimplePractice members who see families and document them in the software.
Currently, if you'd like to create notes for each individual in a family, you'll want to create each individual as a client and then schedule them all in the same time slot.