When you take the Attack action on your turn, you can replace one of the attacks with a casting of one of your Wizard cantrips that has a casting time of an action.
War Magic
Raw data
{
"name": "War Magic",
"page": 98,
"level": 7,
"__prop": "subclassFeature",
"header": 2,
"source": "XPHB",
"entries": [
"When you take the {@action Attack|XPHB} action on your turn, you can replace one of the attacks with a casting of one of your Wizard cantrips that has a casting time of an action."
],
"className": "Fighter",
"classSource": "XPHB",
"subclassSource": "XPHB",
"subclassShortName": "Eldritch Knight"
}