Download TomTom software updates through the company's desktop application, as of 2015. You may have to install MyDrive Connect or TomTom HOME to receive updates, depending on which device you own.
In both cases, you must connect your TomTom navigation device to your computer, launch the required software if it does not start automatically, and click on the Updates button. From there, the software guides you through the update process.
Determine which software you need by checking the compatibility list available on the TomTom website or by reading the device's manual. Software updates for TomTom devices are free for all device owners.