Creating and naming messages groups

To create a group simply tap the write logo in the top right and then add in all the contacts and phone numbers you wish.

To rename a chat:

Find the chat you want to rename and open it, from there select the participants (for iOS 12 or later) and then click on “ⓘ”

Then find the section saying enter group name and select it:

tip:

the name which you set will be visible to every participant in the group

There are several apps available in App Store that will do this