Download Now (v3) [setup] -

: As a "Download Now" feature, it is designed for immediate execution, often bypassing intermediate "Save As" prompts to speed up the user experience.

To give you more specific details, could you share or software program you see this button on? Download Now (V3) [setup]

: The "[setup]" tag indicates that the file is an installer package designed to automatically configure the software on your system. : As a "Download Now" feature, it is