Get Mocklyn for your computer.
Start with a full 7-day free trial. No credit card required.
Download the installer, follow the steps, and open Mocklyn on your computer.
When the app asks, enter your email address to receive a trial verification link.
Open the verification link, then return to the app and start creating.
A note about security warnings
When you first open a newly downloaded app, Windows SmartScreen or macOS Gatekeeper may show an informational security notice.
On Windows, you may be able to select More info, then Run anyway. On macOS, check System Settings → Privacy & Security for the option to open the app.
Only continue if you've downloaded the app from the official Craft Mage website and are comfortable proceeding. The supplied product information states that the downloads are signed and checksum verified.