An authorized user is a court reporter who can charge signatures to your account. The person must be enrolled in the RealLegal Signature service.
On the Billing Accounts page, Authorized User are labeled as shared.
Note about the Purchasing Signatures option: If you are subscribed to the Unlimited Workflow or Unlimited Multimedia plan (that is, you pay a monthly fee for RealLegal products and services), you do not need to purchase signatures. RealLegal provides them as part of your subscription. If you need more signatures, contact reallegalsubscriptions@thomsonreuters.com.
Court reporters, if you use Reporter Edition, your production department may be able to provide you with signatures.