WhatsApp can be activated on almost any number in the world, including virtual numbers.
The default number verification WhatsApp uses is based on text messaging (SMS), where they send an activation code to the number you are trying to register on their network, and upon the reception of that code, your account will be enabled and ready to use on WhatsApp.
A second method is through the reception of a phone call, which works similarly to the SMS method, but instead of obtaining the activation code via text, the code is provided via voice through a phone call.
The former method is desired when your number has a SIM card or eSIM with SMS reception enabled, but in cases where SMS is not available, like with virtual phone numbers, the voice call activation is the only method we can use.
Activation steps
Make sure the virtual number you selected is compatible with WhatsApp. You can learn how to determine this in this article.
Log in to 2Chat and remain online to be able to receive the activation call. You will see a green indicator next to your avatar picture if you are available to receive phone calls.
Open the WhatsApp application and enter the virtual number you wish to register.
WhatsApp will try to send an SMS code to the number, but since virtual numbers don't support SMS, the reception will fail.
Tap on "Didn't receive the code?", and a menu will open that will let you select the option to receive it as a phone call.
You will most likely need to wait between a few seconds to a few minutes to select the Voice call option. This is normal and used by WhatsApp to prevent abuse.
Once the option becomes available, click on continue.
The phone call will arrive and ring all 2Chat sessions where you are online. Answer the call and follow the instructions WhatsApp gives you to get the activation code.
Enter the code given on the WhatsApp app, and your account will be activated!