Right after the installation, Plesk uses a trial license key. To get a new license key, proceed to the Plesk online store (shop.plesk.com) where you can select and purchase a necessary license key.

Once you purchase the key, you will receive an activation email with your activation code and a license key file. You can install a Plesk license key either by entering the activation code or by uploading the file from this email.

To install a license key using an activation code:

1. Go to Tools & Settings > License Management > Plesk License Key and click Install Key.
2. Enter the code you received in the email to the Enter an activation code field and click OK.

To install a license key using a license key file:

1. Go to Tools & Settings > License Management > Plesk License Key and click Install Key.
2. Choose Upload a license key file.
3. Specify the path to the key file you received in the email and click OK.