Quitting from a project means you give up the access privilege to the project including all the drawings and discussions in the project.
The discussions you created and the replies you made will remain in the project, but you wont receive any notifications any more.
1. Quit from [project settings] page
Login to the team page, click the top right button, go to the [project settings] page, and exit directly.
2. Ask the project manager to remove you from the project
The project administrator enters the [Project Settings] page and can add or remove members in batch