Hi Akhil,
EL is the standard inbound delivery type that is created with reference to a Purchase order in the Import scenario (if we consider it from the point of view of SAP GTS).
Actually, in the area for GTS Plug-In in the feeder system and further in the node: Configure Control Settings For Document Transfer, you could see the entry for Application area MM0B (Inbound delivery). Under this Application area itself, the concerned inbound delivery type EL is defined with relevant services. This document type can be configured for services on the Compliance and Customs Processing areas.
Hope, you got your answer now.
Regards,
Aman