Dear Manoj Wijesooriya
Welcome to the Microsoft Community, we are glad to assist you.
We understand that you want to add a “Comments” column to Loop's tasks list.
We would like to explain that in Loop, when you create a new Tasks List, there are four columns by default, Task, Assigned to, Due date, and Bucket, and these four columns cannot be changed.
We have tested and found that it is not possible to create new columns in Tasks List.
Improved task list components in Loop (microsoft365.com)
However, considering your needs, may I ask if you are using the Bucket column? This column is categorized by tags, but you can add comments to this column if you want.
We also recommend that you submit your request to the Loop team, as it would be a great suggestion to add a new column, either in the Loop software or on the web (please provide as much detail as possible, including images, copying videos, etc., if convenient), where a dedicated developer will look at it and comment on your feedback.
After sending in your feedback, you can share the feedback link in this forum so that other users with similar issues, including me, can vote for your feedback, the more votes the more likely it is to get the attention of the development team, thank you for your cooperation.
Finally, while I can't help you any further, I hope the information I've provided has helped you find a better direction. If you need our assistance in the future, please feel free to contact us.
Thank you for your interest in Microsoft products and your understanding.
Best Regard
Tracy | Microsoft Community Support Specialist