If you are concerned about people adding you to WhatsApp groups without consent, there are a few settings you can modify to adjust how others can include you. Firstly, from an iPhone, go to options, then Chats, then Groups. You will see an option that says 'Allow Others to Add Me to Groups' which you can toggle off; however, doing so will prevent you from being added to groups without your confirmation in the future.
To prevent others from adding you to groups without your knowledge in the short term, you can use a simple permissions manager. From the chat screen, click on the contacts icon and then Groups. There will be a "Join Group Invitation" text indicator next to your name, which needs to be tapped to allow or decline future invitations. One will have the option to decline after tapping on this indicator, then click block from the pop-up screen that shows up after tapping the "Block and Ignore" option. Click decline or accept as needed after that.
The same steps should work for Android as well although settings placement might differ. Go to Settings > Profile Settings > Groups. Swipe down to Group Participation, toggle it off to stop future initial requests and ask to join instead. The steps are the same to decline and whatsapp安卓下载 block an invitation if needed.