Visitor parking permits are issued by the Metropolitan Police Department. These are one-time permits that are issued specifically for your guest (you must provide your guest’s name and license plate when applying).
Visitor parking passes are issued by DDOT. They are a valid for an entire calendar year, and are not specific to a particular guest. Whenever someone visits you and plans to stay for more than 2-hours, they can display the pass on their dashboard to avoid being ticketed.
Note: Visitor permits and passes are only needed in areas that are zoned for Residential Permit Parking.