8:18-cr-00012-TDC
The 8 designates which court location of the filing within the District of Maryland. 18 = filed in 2018. CR means its a criminal filing. 00012 means it was the 12th case filed in that district court in 2018 (likely filed in January 2018). TDC is the initials of the assigned judge. There isn't a number after the judge's initials on this filing (eg TDC-1 or TDC-2), but that number represents which defendant it is in a multi-defendant case).