Is there a way to make a non-magical weapon magical?

If a Wild Magic Barbarian uses their ability to restore a spell slot to a warlock, does it only work if they can hit the warlock’s only spell slot level on the d3?

Errata, Warlock quick build – Ray of Sickness is not a Warlock spell

Great Weapon Master feat, can I take the bonus attack on crit?

Hi guys, if I have the Great Weapon Master feat, can I take the bonus atk on crit or kill with one hander?

If a player has Polearm Master feat, but is using a spear or quarterstaff 1 hand with a shield, does the feat still apply?