Go to the project manager and find the design you'd like to delete. Then click on the cog wheel icon and click on the "Delete" button. After that, you will be prompted to confirm the deletion of the design.
Tip: If you're using the Desktop App you can simply select the project or the design and press Cmd + Backspace (Mac) / Delete (Windows)
If you accidentally delete a design, you can contact us and we'll renew it.