You can attack twice instead of once whenever you take the Attack action on your turn.
Extra Attack
Raw data
{
"name": "Extra Attack",
"page": 15,
"level": 5,
"__prop": "subclassFeature",
"header": 2,
"source": "EFA",
"entries": [
"You can attack twice instead of once whenever you take the {@action Attack|XPHB} action on your turn."
],
"className": "Artificer",
"classSource": "EFA",
"subclassSource": "EFA",
"subclassShortName": "Armorer"
}