If the online loan does not receive the poster's email, you should contact the sender if you want to return it.

This should be signed, and it will not affect the judgment.

If there is a charge for express delivery (not from your friends or relatives), don't sign for it in a hurry. The best way is to contact the sender. If the sender can't contact or has no contact information for collecting express delivery, I suggest not to sign for it. If it is not a fee-based express delivery, then there will be no worries about signing or not.