Comma is a punctuation. use it:
To Separate Numbers
In Written Dates
April 08, 1966August 17, 1945
Before The Quotes In Direct Speech (…, “…”)
He said, “I am so hungry.”
Arman said, “Indonesia is a beautiful country.”
You said, “I will be responsible for that.”
To Separate Elements In A List Of Three Or More Items
List of nouns:
He buys a novel, a history book, a magazine, a Grammar book, and a newspaper. (USA)
They eat banana, mango, coconut, apple, jackfruit, orange and pineapple. (UK)
List of Verbs:
We enjoy playing badminton, hiking, fishing, surfing, skiing, and dancing. (USA)
I enjoy reading magazines, reading novels, reading newspapers and reading history books. (UK)
After Subordinate/Dependent Clause When It Begin A Sentence
Although he did not study last night, he could finish all the exercises
When you called me, I was sleeping
Before Coordinating Conjunctions (for, and, nor, but, or, yet, so)He came to library yesterday, but did not read any book
You are his brother, so help him.
You come here, or I come there.
He tried to finish all the exercises, yet he did not know the answers
He did not eat the mango, nor ate any food.
I don’t like spicy foods, for it burns my tongue
Dony came home yesterday, and he helped me cleaning the room
After connective Words (however, consequently, moreover, Unfortunately, etc.)
Unfortunately, he doesn’t know the answer of the last question.
Finally, he won the game.
Before and After Additional Information In A Sentence
He, consequently, decided to go to Bromo Mountain
Mr. Latief, who was the teacher of the school, help the students to cross the street