You can find the menu on the printer's control panel below.
Settings > General Settings > Fax Settings > Send Settings
On the Web Config screen, you can find the menu below.
Fax tab > Send Settings
Set the time to wait for the next original. The printer starts sending the fax after the time has passed.
You can preview the scanned document for a set time before sending it. The printer stars sending the fax after the time has passed.
This item is displayed on the Web Config screen only. Enables sending faxes using a client computer.