Because Courier Final Draft is a proprietary variant of Courier 10 BT, it is not typically available as a standalone commercial purchase. You can acquire it through the following methods:
The font is automatically installed on your system when you download Final Draft. Even after a free trial expires, the font files usually remain in your system’s font folder. courier final draft font download
If you don't own Final Draft but need the same professional "look" and pagination, these alternatives are widely accepted by agents and producers: Because Courier Final Draft is a proprietary variant