My IPhone 14 Pro won’t let me send group texts. Where do I go to set that up?

Types of group messages

The three types of group messages that you might see are: group iMessage, group MMS, and group SMS. The Messages app automatically chooses the type of group message to send based on you and your recipients' settings, network connection, and carrier plan. For example:

• If you and your recipients are using Apple devices and iMessage is turned on, then the group message is sent as an iMessage.
• If you send a group message to people who aren't using iMessage, then the message is sent as an MMS or SMS message.

You may not have an SMS plan enabled by your carrier for the SIM/eSIM that you use on your device. Apple Inc does not provide SMS services.

To enable that feature : go in settings then click on messages , go down the list and you will see ware you can flip the switch to the on position .

did you check your message settings to see if you have sms enabled so you can text people who do not have iPhones? I’m assuming you do but I would check all settings under messages.