how to use whatsapp with fake number for free???

i have been trying to find a free method by which i can send messages to people with a fake whatsapp number.many of the things i found were not working so i am asking for help here.
One more things i have added so many groups to my whatsapp but as you all know no one pays attention to the groups messages so i am sending the messages indiviaully but it takes too much time so is there any trick that i can send messages indiviaully to everyone in the group automatically.:):):):):):):):) need…

how to use whatsapp with fake number for free???