If I reset my phone will I be exited from all groups in whats app?
Not really.Your WhatsApp backs up everyday either to Google drive or to your storage (you'll be asked to do enable it). The account will be removed when you reset your phone and so does the storage will be erased. Before you click on the reset, you'll be asked for backup options which even includes the WhatsApp database.So even if you reset your phone, you'll not be removed from other groups but your previous messages will be lost (If no backup file exists in your phone).