You can get the unlock key directly from TallyPrime by pressing F1 (Help) > Settings > License > Manage License > press F6 (Unlock).
Alternatively, you can get the unlock key from Tally Solutions website, by providing the Tally product serial number.
Go to the Tally Solutions website.
Click SUPPORT.
Scroll down, and click Get Unlock Key for Activation. The Unlock Key Service screen appears.
Enter the Tally product serial number, and click Get Unlock Key. The unlock key for your Tally Product serial number will be displayed.
You can use this key to unlock and use your Tally product.