You can have as many users as you want to. Just go to your profile and select add user. You can set different levels of access to your account depending on what you want them to be able to edit. For example if you want someone to have access to everything to help you manage your operation then that is fine. Also if you have a mechanic that is handling your maintenance and you want him to enter all the repairs that he performs you can give him access to the maintenance without giving him access to the whole company.