Each chosen creature still controlled by the active player becomes an attacking creature. It remains an attacking creature until it’s removed from combat or the combat phase ends, whichever comes first. See rule 506.4.
January 25, 2019 · Ravnica Allegiance
Each chosen creature still controlled by the active player becomes an attacking creature. It remains an attacking creature until it's removed from combat or the combat phase ends, whichever comes first. See rule 506.4.
April 28, 2017 · Amonkhet
Each chosen creature still controlled by the active player becomes an attacking creature. It remains an attacking creature until it’s removed from combat or the combat phase ends, whichever comes first. See rule 506.4.
September 30, 2016 · Kaladesh
Any abilities that trigger on attackers being declared trigger.