By this do you mean in-game comments?
Notes
Well after the game is over, and you're doing review...can you add notes in after the game is over?
For this I'm not completely certain. I am only familiar of adding my own in-game notations post-game.
If you have a game to be posted, you can download its PGN and insert it here. Do you know where to extract the PGN from?
One thing though. Beware!
This site has some issues when making a post for the first time. Before you post the game, make sure you just type some random chat here, then post it, then edit the chat to include the game. Do not try to include the game at first try or all your annotations will disappear.
1. Make a random post like this.
2. Edit the post.
3. Insert the game and annotations.
You can do a test run by using the two-move checkmate above to see this. The game comments will disappear if you straight away post the board without editing it first.
EDIT:

I think i found it on notes section of game...don't know if i can do it after game is complete. I'll look. ty sir

You can also use the Analysis Board and the option to Save Analysis or add games to a Library Collection.
https://support.chess.com/article/1306-how-do-i-save-an-analysis
https://support.chess.com/article/1305-how-do-i-find-my-saved-analysis
https://support.chess.com/article/1987-how-do-i-use-the-chess-com-library
Where can you put notes in a completed game?