The process for signing a Will varies state by state. Generally, you'll need to have at least two witnesses present when your Will itself is signed. In fact, those witnesses are there to attest to the fact you're competent and weren't coerced into signing anything you didn't want to.
Best practice is that these witnesses aren't named anywhere in your Will. This keeps them impartial. If you sign your Will at your attorney's office, your attorney may choose to have a partner or a paralegal serve as witness.
Your Last Will and Testament won't do you much good if no one can find it. That's why you need to take steps to distribute legal copies to your attorney, your executor, your spouse or any other close family members. It's also smart to keep a copy in a safe place at your house, just in case you want to make changes or just refresh your memory about what you've decided.