Microsoft Planner is an intuitive, collaborative task management tool available through Microsoft 365. It enables people to plan, manage, and complete task-based initiatives. With Planner, you can create plans for simple projects. Each plan has its own board, allowing you to effortlessly collaborate around tasks, including due dates, status, checklists, labels, and related file attachments.
For an overview, check out the Microsoft Planner product page and training page.
Unfortunately, there is no recycle bin for Planner. If you delete something, it is immediately purged. If this is a major concern for your use case, you might consider trying Microsoft Lists as an alternative, which has version history capabilities.
Removing the plan tab only removes your plan from Teams, it does not delete it. If you want it back, simply add a new Planner tab and select ‘Use an existing plan’. If you need to verify the plan still exists in Planner, you can do so by logging in directly to Planner at https://tasks.office.com