Should have big motives
Decisions are the main factor that decide whether the character will be a protagonist or antagonist or a regular character in the story. The protagonist should have big motives that put him or her in a do or die situation.
Should be heroic
The main character should inspire and motivate the views and should do something heroic like saving someone’s life or disclosing the secret of the antagonist.
Should be the main force to drive the story
The main character is the protagonist of the story and the story should revolve around the protagonist. You should try to talk about the protagonist as much as you can in the whole story plot.