Understand what the Quick Collection is and how to use it
The Quick Collection is a temporary collection in the Catalog area of the Library in Lightroom. You can use it to manage your images.
You can drag and drop images into the Quick collection and use it to store images temporarily.
The Quick Collection doesn’t lose its contents when you close and reopen Lightroom.
When you right click the Quick Collection you can choose Set as Target Collection, Clear Quick Collection or Save Quick Collection to save its contents as a regular Collection.