Yes, Latvian law allows this. According to Paragraph 42 of Cabinet Regulation No. 877 of the Republic of Latvia “Accounting Record Keeping Regulations”, a goods delivery document does not need to be signed if it is prepared electronically and the parties to the transaction (the sender and the recipient of the goods) have agreed to this based on an agreement regarding the delivery of goods.
Therefore, such an agreement may be included in a written contract between the seller and the buyer or in the website terms of use accepted by the recipient when ordering goods through an online store.