How to send a group text to more than 10 people? How can I send a group text to a group of 11 people that do not all have an Apple phone?  I have iPhone 6.
A group message can be sent either as an iMessage or an SMS. Just create the group to which you wish the message, the Messages app will automatically choose the appropriate message type based on recipients' settings, network connection, and carrier plan.

In depth guide on sending group message can be found in the Apple Support Document, Send a group message on your iPhone, iPad, or iPod touch.