You use Google and search for it, like the rest of us. To get the answer on how to do it.
or was that thought not apparent to type it into Google.
I mean how do you think we do it ?
And the sentence you typed does not make sense to start with.
It should of been I just bought a WD Elements external, portable drive, I want to format the drive so I can read it on a Mac laptop, or tower system.
If the case then all you do is plug it into the Mac.
And it will ask you to format the drive so the Mac creates a file system it uses to read and write data to the drive.
In other words plug the drive into the Mac not a windows machine to format the drive, for the Mac device to be able to read the drive. Or go here for support on how to do it.