UPS will require the signature for the evidence under the following circumstance
Delivery Confirmation: UPS will send you a mail of confirmation of delivery without a signature. Please note that similar information is also available when we track our package online.
Signature Required: UPS will take the signature of the recipient or will take another electronic acknowledgement receipt from the recipient of the mail. When you select this option it will give you a printed copy. You may also need to see the recipient’s signature or electronic acknowledgement of receipt online.
Adult Signature Required: UPS usually take the adult mail signature of the recipient and will give you a printed copy. Adult recipients must be of age at least 21. You may also need to view the adult recipient’s online signature.