"Does this mean they will be the executor and deal with all the paperwork."
It's entirely up to you to decide who is your executor. Most people like to appoint a trusted family member, or a solicitor, or both. I have acted as executor in the past, and it's a pretty straightforward process - an executor's main function is to ensure that the deceased wishes in relation to the disposal of his/her estate are adhered to.
You should consider whether appointing a third party who is not known to you, and is not a member of the legal profession is a wise move.