Look in your owner's manual for programming the keys.
We bought 2013 Chrysler, I bought extra keys on-line and programmed them myself.
From our owner's manual:
Customer Key Programming
You can program new keys to the system if you have two valid Sentry Keys® by performing the following procedure:
Cut the additional Sentry Key® Transponder blank(s) to match the ignition switch lock cylinder key code.
Insert the first valid key into the ignition switch. Turn the ignition switch to the ON/RUN position for at least three seconds, but no longer than 15 seconds. Then, turn the ignition switch to the LOCK position and remove the first key.
Insert the second valid key into the ignition switch. Turn the ignition switch to the ON/RUN position within 15 seconds. After ten seconds, a chime will sound. In addition, the Vehicle Security Light will begin to flash. Turn the ignition switch to the LOCK position and remove the second key.
Insert a blank Sentry Key® into the ignition switch. Turn the ignition switch to the ON/RUN position within 60 seconds. After 10 seconds, a single chime will sound. In addition, the Vehicle Security Light will stop flashing. To indicate that programming is complete, the indicator light will turn on again for three seconds and then turn off.