How to delete an opportunity / todo / note ?
Delete Project: Click into the opportunity detail, then in the context menu, click 'delete opportunity'.
Delete Note: Click 'more' icon, click 'delete '.
Delete to-do: Click 'finished', After clicking to finish the to-do on the computer, it will always be archived in the to-do list, arranged after the unfinished to-do.
In most cases, you could simply swipe the row in mobile CRM app to find out the corresponding delete / archive options.
The deleted items will be removed from the screens, but corresponding action records could still be seen in the history tab.