Used goods are declared using the declaration form. The declaration form includes your name, address, citizenship, and ALL the items in the package. (For convenience items may be categorized). You will need to fill out the product description, estimated value, quantity, and years of use. (A product with no years of use is considered new and requires an invoice).
A package valued above $75 is charged a tax of 17%  by the Israeli tax authorities. In such an event, an Israeli citizen will need to provide a Teudat Zehut number and a non-Israeli will need to provide a picture of the passport of the declarant above the age of 18.