WhatsApp is a freeware, cross-platform, centralized instant messaging and voice-over-IP service owned by United States tech conglomerate Meta Platforms [wikipedia].
How to create a WhatsApp group with a single participant?
As of Sept 5, 2023, there's no way to create a group chat without adding a 2nd participant (1st participant being yourself) when you create a new group.
Creating a group without adding a 2nd participant is useful because there are situations where you may want to create a new chat group in order to generate an invite link that you can then share with potential participants.
As a workaround, you can add a friend as the initial 2nd participant and then immediately remove them. Alternatively, you can add Twilio's WhatsApp Sandbox Test phone number, +1-415-523-8886, as a contact in your address book, and use it as the initial 2nd participant.