Yes, you can easily update Garmin GPS. It can be done either by using free Garmin Express program or by downloading and installing community created maps from any unaffiliated website. It is quite crucial to update your Garmin GPS device on a regular interval. This will assure you that you are navigating on the basis of latest maps and features.
Although, with my experience, I always recommend to update Garmin maps using Garmin Express app which is totally free and a much easier method.