"I pledge allegiance to the flag of the United States of America, and to the republic for which it stands, one nation under God, indivisible, with liberty and justice for all."
The flag consists of 13 alternating red and white stripes that represent the 13 original colonies, and 50 white stars on a blue field, with each star representing a state. The colors on the flag represent:
The U.S. flag stands for our nation and the shared history, pride, principles, and commitment of its people. When we properly display this powerful symbol, we signal our respect for everything it represents.
The flag shouldn’t be flown in inclement weather unless it’s an all-weather flag.
Flags displayed at night should be properly illuminated.
In a time of national mourning, hang the flag at half-mast.
The flag can be flown every day, but it is often flown to show patriotism on these observances:
New Year’s Day
Armed Forces Day
When displaying the flag…
From your porch, place the union (blue section) at the peak of the staff.
Against a wall or on a window, place the union (blue section) at the top left corner.
On your vehicle, clamp the staff to the right front fender.
With another flag, place the U.S. flag to your left when crossed.
Keep your flag completely dry and folded properly — into a triangle, with the union (blue section) visible — before storing it in a well-ventilated area. If the flag is damaged or worn out, it should be disposed of with dignity.
The flag should not touch anything below it or rest on the ground.
Source: United States Code, Title 4, Chapter 1–The Flag
While you can follow how the executive branch flies the flag, it is not a requirement. For instance, a local community, a company, a school district, or a federal agency can decide to have all of their flags at half-staff because of the death of an employee, a student, a mayor, or a local police officer.