Always use a comma when directly addressing another person. When you talk to them by name, you must insert a comma after their name.
Mary, please set the table.
Mom, I won’t be home for dinner tonight.
Always place a comma after a name when the name is used in a direct address.
It’s your turn. Where should the comma be placed in this sentence? Dad the car has a flat tire. Did you put it after the direct address? Good for you!