I’m am wanting to add a second drive and does it have to be formatted first?
I suppose that depends on what you mean exactly. A new drive will need to be formatted before you can use it, but not before you install it. If it’s an external drive they usually come pre-formatted. The process can vary depending on what version of linux you are using or if you are using an LVM. If you are using version with a GUI they generally walk you through the process pretty easily.