This is NOT about "real"-vs.-"fake" IDs. Rather, it refers to the REAL ID requirement of the United States Department of Homeland Security (DHS) and Transportation Security Agency (TSA), which is a set of requirements for IDs that the TSA will accept at U.S. airports.
The REAL ID Act is a federal requirement for identification documents in the United States.
A "REAL ID" will be required for boarding all federally-regulated commercial aircraft (this includes both domestic and international flights). However, several states have been granted extensions for the IDs they have issued, and the precise details may vary across states.
Several federally-issued documents (such as passports, passport cards, and Global Entry/NEXUS/SENTRI cards) currently also qualify as REAL IDs.
For more information, see:
Your state's Department of Motor Vehicles (DMV) website (recommended)