In the end==finally. It is often followed by a comma. at the end is followed by of. At the end of his life ,At the end of every sentences

"In the end" is used mostly as an idiom that means "finally," "after a long time," or, "when everything is considered." It is often followed by a comma. We worked hard, and in the end, we achieved our goal. "At the end" is most commonly used more literally, as a prepositional phrase followed by of, to refer to the end of a specific noun. This noun can be a physical object, a period of time, an event, a place, or something more abstract, such as one's patience. At the end of his life, he had no regrets. Put a period at the end of every sentence.