The Package originator has the ability to enable or disable the Review Documents option while creating a Package. When creating and customizing a Package, click on the Reviewing tab in the Package Options.
Under Reviewing, there is a Documents toggle switch to enable or disable the ability for the signers to review the documents in the Package before signing. By default, the toggle switch is enabled.
The Signers will now be able to review the documents before signing.
You can set this option as default for all your future Packages by
updating the Signing Defaults values: Set Your Signing Defaults