You certainly can, all packages are signed for when delivered. Don't forget, however, to ask for a signature for collections too - we suggest that you print a copy of your order to be signed by the courier who picks up your parcel.
We're a firm believer in accountability, and so are our parcel delivery partners. As such this means that all parcels should be signed for when delivered. Some traditional services just require a signature on a piece of paper. However all of our partners require an electronic signature on their clever hand--held devices that allow the online tracking services to be updated 'on the fly'.
A signature generally would mean that the parcel has been received in an acceptable condition, and hence may affect your ability to claim for damage. Please make sure you have read the terms and conditions before you book (currently Section 5 details the terms related to making a claim.)
Just make sure you are aware of the terms and conditions and for the recipient to know what their signature denotes.