You can use WinTask x64 freely for evaluation purposes only for 30 days. After that time you must purchase a fully licensed copy.
To purchase the software, visit the WinTask x64 purchase web page (www.wintask.com/buy-wintask.php). When the registration is complete, you will receive your registration key.
To enter your registration information, start WinTask x64 and in the first screen, click Enter License Key. Enter your registration key by copying/pasting the 3 lines which have been emailed to after your purchase.