this response will be translated automatically. therefore, there may be grammatical errors or strange wording.
Hello KKChen2!
welcome to the microsoft office community forum. thank you for sharing your concerns with us today and we wish you all the best.
I fully understand your concerns about the Microsoft To Do app, you tried to remove the column, but it removed the entire comment. Let's check and sort it out together. Rest assured, I will do everything I can to help you solve your problem.
First of all, I would like to know what type of device you use on your Android phone or iOS device?
answer your questions;
if you use your phone after deleting a task on the to-do app, sorry to tell you that there is no restore option or trash to store the deleted items, but you can choose to undo the completed activity.

This is a feature that is not yet available on the software. that being said, we recommend that you send a feature request to our developers about this issue. in this way, they will realize where improvements are needed, which will benefit users like you. to provide feedback, you can go to settings in the to-do app and you'll see the suggestions option. to find settings, just tap on your profile. take a look at the image below.


to delete the completed task/item individually, you just need to swipe left and you will see a delete option. take a look at the image below.

hope it helps. if you have any questions about this, please let me know.
honestly
raynaldob
MODERATOR OF THE M365 CONSUMER FORUM
microsoft community