How to select all contacts when sending text messages on iphone 6?

1. Click the phone to enter the SMS editing page. Then, as shown in the figure, we click the "+"button in the upper right corner to add recipients.

2. After selecting the recipient, the mobile phone system will automatically jump to the SMS editing interface. Don't worry, just click the "+"button at the top right, and you can continue to add. If your page doesn't have a "+"button, just click it in the recipient column.

3. After adding a contact, you can edit the content and send a group message.