Many couriers offer the option to require a signature from the receiver from on delivery. You can request this on your parcel but selecting the 'Signature Required' tick box at the Calculate Freight step.
Depending on the courier, this may be a free of charge or it could cost a small fee.
The opposite of Signature Required is called 'Authority To Leave (ATL'. You can default your preference under Administration --> Preferences and Settings and selecting 'Default service to non-signature (ATL)'.
Some couriers offer a Saturday Delivery service in the event that the parcel cannot be delivered on a weekday (or you are sending it on a Friday). You can opt into this by selecting the 'Saturday Delivery' tick box at the Calculate Freight step.
Saturday Delivery is an extra charge, some couriers charge it at the point of label creation and others require you to purchase a pre-paid Saturday Delivery ticket.
Parcels selected to be delivered on Saturday Delivery also require extra labelling. If Saturday Delivery stickers are not attached to the parcel it is unlikely for the item to be delivered on Saturday.