Can I link my Jeppesen Military Charting Service (JMCS) account to ForeFlight Mobile?

Yes. If you already have Jeppesen Military Charting Service (JMCS) credentials, then you can use those credentials to access Jeppesen data by linking to your Jeppesen account under More > Jeppesen in ForeFlight Mobile EFB or MFB. If you do not already have JMCS credentials, you can register for those credentials here: eCharts Online Registration