The phrase "adding his comments" is correct and usable in written English.
It can be used when referring to someone contributing their thoughts or opinions to a discussion or document.
Example: "During the meeting, he was adding his comments to the proposal, which helped clarify several points."
Alternatives: "providing his input" or "offering his remarks".
On 7 January this year, Mr Fisher commented on a headline saying the former Prime Minister could face war crimes charges over the Iraq war, adding his comment: "Long overdue – let's hope so".
A deputy comptroller, Robert B. Ward, described Mr. Megna's reaction as "puzzling," and added, "His comments regarding our staff were off base and miss the point".
Completed guides are forwarded to him, so that he can add his comments and create an original drawing for each child.
The instructor who composed these specimen speeches for fictitious court cases adds his comments and suggestions concerning presentation and arguing tactics, thereby giving us insight into Roman law and education.
Among those who added his comments was Taylor Batten, recently promoted to an editing job, who wrote "the paper, which should love this community, abdicated its role by failing to take a stand one way or the other". Mr. Batten's name has resonance beyond his own newsroom; he is the son of Knight Ridder's longtime chief executive, James K. Batten, who died in 1995.
Tesla and SpaceX CEO Elon Musk added his comments via Twitter late on Saturday afternoon.
NASA Administrator Charles Bolden added his comments late Thursday afternoon, saying Glenn's legacy is one of risk and accomplishment.
It will not be announced by the president at all, but instead by his head of the Environmental Protection Agency, while President Obama adds his comments in on an off-camera conference call with health advocates.
After a medical expert reviews the data and adds his comments, the result is sent to the mobile console for display.
Some citizen had added his comment.
