Using WD Passport and Adobe Lightroom

Hi all.   I have just downloaded the new Adobe Lightroom and I would like to make a copy of my photo originals directly on to my WD Passport for Mac drive so as to not take up space on my laptop.  Is it possible to send data directly the the external hard drive and bypass the computer HD? 

it will depend on the app. I haven’t use the lightroom, it might have an option to allow you to save the files to a different location than the internal HD

Hi thanks for the response.  Lightroom does let me save to places other than my hard drive.   I am showing my ignorance now but what is the file pathway name I use to get things direct to my external hard drive. regards M