You must already be enrolled in VA Health Care to apply for VHIC.

Once you have enrolled in VA Health Care, you can have your picture taken at your local VA medical center, and a VHIC will be mailed to you.

https://www.va.gov/healthbenefits/vhic/

You must bring your current, unexpired:
State-issued driver’s license, or
U.S. passport or passport card, or
Other government ID issued by a federal, state, or local government agency
Note: This ID must show your picture and date of birth. If it doesn’t also show your address, you’ll need to bring a separate document to confirm your address. This may include your electric bill, cable bill, voter registration card, or another mailed document (cannot be any mail you have received from the VA)