Should I Add Signature Confirmation on Ebay Packages?

Generally “no”, USPS Tracking is good enough for most situations.

However, if the price will be $250 or more, you should add Signature Confirmation, because PayPal requires it as proof of delivery on larger orders.

The fact you require Signature Confirmation should be disclosed in your description.

Also, it’s worth considering for some items that may be subject to fraud, like cell phones. This is where the buyer may report that the item was not delivered, or was delivered damaged.  You don’t want the postal carrier leaving behind an expensive item on the doorstep.