Back in July, Microsoft added the ability to include comments on Microsoft list items. While I like the idea of being able to comment on list content, it may be something that doesn’t work well for certain styles of work or list content. To remove that distraction or avoid overlooking comments, you can turn off comments in a list. Here’s how you do that…
In the Settings for your list, select Advanced settings:
In the Comments section, set Allow comments on list items to No:
Scroll down to the bottom of that screen and click OK to save the setting. You will no longer be able to add comments to that particular list.