Please, note that for this plugin, you do not need to activate the license right away in order to use it. You need to activate it when you want to update the plugin to a new version.
Please, go to WooCommerce » Settings » Pack IQ. Then, click on License.
Copy your license key and paste it into the license key field and then click on “Activate“. The page will inform you that you successfully activated your license. Now, you can get back to the plugin’s settings page and configure it as you wish.
You can find your license key on your purchase history page, scroll down to your purchase and click on “View License”. An alternative is your purchase receipt email, which looks like this: