While generating an E-Way Bill, you have to opt for ''Recipient not known'' sub-type when Goods are being moved to another place but the actual buyers of the goods are not known at the time of start of movement. For eg- If any person has to move his goods to a marketplace where he'll find many customers, he'll select the "recipient not known" sub-type.
The "Line sales' sub-type is very similiar to the above mentioned subtype. "Line sales" is generally used for door to door selling of goods.
However more clarification is required from the GST Council regarding the correct situations for usage of both these subtypes.