If you are a WhatsApp user, then you know how to add multiple contacts in the same WhatsApp group at once. However, if you are not a WhatsApp user and want to add multiple contacts in a WhatsApp group at once, then there is a way to do it. To add multiple contacts in a WhatsApp group at once, first open the WhatsApp app and sign in to your account. Then, click on the three lines in the top left corner of the main screen and select Add Contact. Then, enter the name of the person you want to add as a contact and click on Add. Now, select all of your contacts and click on Add All. Now, your WhatsApp group will be filled with new contacts.