Yes. Stages Link is compatible with a large range of head units and other sensors, as well as having the option to input ride time, distance, and other ride metrics into the calendar as a manual entry. Anyone can utilize Stages Link to log their cycling data, track their performance, and follow a training plan.
We do highly recommend using a cycling computer or app that will record your data and upload it to Stages Link alongside either a heart rate sensor or a power meter in order to best take advantage of Stages Link training plans. If your cycling head unit can record a ride and upload it to the computer, it is most likely compatible to be used with Stages Link. For smart phone apps, the app should have an option to save the file by emailing or uploading in order to be able to add it to your Stages Link account.