For high-value or secure packages Amazon requires a One‑Time Password (OTP) that must be given to the delivery driver upon arrival. You can enable this in your account settings or during checkout:
• During checkout or in Your Orders, click Track Package → Provide Delivery Instructions, and set access details, intercom #, or indicate OTP requirements.
• On delivery day, Amazon emails a 6‑digit OTP to your registered email, which you show to the driver to receive the package.

FedEx – Access Codes & Express Instructions

FedEx’s Home Delivery service lets you provide delivery preferences and special instructions:
• Use FedEx Delivery Manager (either online or via app) to:
• Schedule evening or weekend delivery windows,
• Leave precise instructions (e.g. “leave by back door”),
• Apply access codes or gate instructions for secure properties