There are two different ways to activate QuickBooks desktop after installation.
- Activate it over the internet by filling in your details using a built in QuickBooks registration form. Internet connection is required
- Using a Validation / Activation code. No internet connection is required.
Activate over the internet
If QuickBooks haven’t prompt you yet to active it so far, then from the top menu select HELP > ACTIVATE QUICKBOOKS DESKTOP. (In some older versions you may see Register QuickBooks option instead.)
A built in QuickBooks registration form will appear. Fill in the form with your details and follow the instructions to register / activate the product.
In case where the registration form does not appear on your screen or this activation method fails then this might be because an antivirus and or a firewall system that might be installed on your system is blocking QuickBooks from communicate with activation server over the internet. You can try disable your antivirus or the firewall and try again.
activate using a validation / activation code
If the Internet activation fails, then you may want to try to activate your product using an activation code. If you do have your activation code handy then from the top menu select HELP > ABOUT QUICKBOOKS. On your keyboard press CTRL+R+P. Type your validation code in the appropriated field.
This YouTube video may help you further: https://youtu.be/SDdQBKw1zs4