In order to add a virtual copy to a collection, you need to create a virtual copy. Once it is created, set the collection(to which you want to import the images or virtual copies to) as Target collection.
Once this is done, you need to select the image or the virtual copy and press B to Add to Target collection.
Note : Add to collection doesn't create any copy of image file.
Also, if you delete the virtual copy from the catalog, it will be removed from the collection as well.
Let me know if this helps.
Thank you Mrinmay.
I was adding an unnecessary step before.
I am glad that I was able to help.
Let me know if you have any further queries.
I am wondering or even hoping that this functionality had changed in anyway, is there today a key combination that will allow me to drag images to a collection as virtual copies?
This work: If I select a set of images and create a new collection I can add the selected files as virtual copies, there is no need to create the virtual copies then add them to the catalog.
Depending on the number of images it is almost worth selecting the images, creating a new temp collection as virtual copies then drag the virtual copies into the correct collection then remove the temp collection.