1. A method comprising: determining, based on communications between a service provider application executed on a server system and an authorizing device associated with an authorizing entity, that a shared service from a plurality of services managed by the service provider application has been specified by the authorizing entity, wherein the shared service and the plurality of services are accessible by end-user devices via a data network, wherein the authorizing entity is subscribed to the shared service, wherein the authorizing entity comprises an entity (i) having a subscription account with the service provider application and (ii) that accesses the service provider application by providing authentication information that matches subscriber information in the subscription account, wherein the subscription account include contact information for the authorizing entity; creating, by the service provider application, (i) a credential and (ii) association data indicating an association among the credential, the authorizing entity, and the shared service that is specified by the authorizing entity; transmitting the credential from the service provider application to the authorizing device; receiving, via additional communications between the service provider application and a third-party device associated with a requesting entity, a request for the requesting entity to access the shared service, wherein the requesting entity is separate from the authorizing entity and is not subscribed to the shared service; verifying, by the service provider application, that (i) the request includes the credential and (ii) the association exists among the credential received in the request, the shared service, and the authorizing entity; providing, by the service provider application and based on verifying that the request includes the credential and that the association exists, the requesting entity with access to the shared service, wherein the requesting entity is restricted to accessing specific types of transactions of the shared service based on an authorization that is (i) specified by the authorizing entity and (ii) identified by the credential as authorized by the authorizing entity; and performing, by the service provider application and responsive to providing access to the shared service to the requesting entity, operations comprising: generating an invoice for use of the shared service by the third-party device using the credential, and transmitting, to the contact information from the subscription account, the invoice for use of the shared service, wherein the determining, the creating, the receiving of the request, the verifying, and the providing of the access are executed by a processing device of the server system.