One of the features of WhatsApp prevents groups from adding you without your consent

Finally, you can control whether you are added to any group or not, especially those that are annoying, before you have to join them and then leave them.
This is done by going to “Settings” >> “Privacy” >> “Groups”, and there the user can specify who can be added after choosing between three options: “Everyone”, “My contacts”, or “No one”. "Nobody".
It should be noted that this feature will be launched soon in the coming weeks.