If you are getting started with APRS, then the easiest was will be to do it on your Smartphone. This post is only about using Android phones, obviously. The clue is the “droid” part of APRSdroid.
NOTE: for this you WILL require an Amateur Radio License and Callsign. If you do not have a Callsign, then I suggest you just watch what is going on on the APRS.FI website.