"由快递公司传递" can be translated into English as "delivered by a courier company" or "transmitted via a courier service".
"Delivered by a courier company" is more commonly used when referring to the physical transportation and delivery of packages or documents.
"Transmitted via a courier service" could also be used, though it's slightly less common in everyday contexts and might imply a broader range of services, including possibly digital or informational transmission in some contexts, though primarily it's understood in the context of physical delivery.
For most practical purposes, especially when talking about packages or mail, "delivered by a courier company" is the most straightforward and accurate translation.