Using Messages on the Mac or in iOS is pretty easy. Start a new conversation, enter someone’s phone number or email address, and start chatting. And if you want to talk with several people at once, type a couple of phone numbers or email addresses when you begin.

What you may not realize is that if everyone in your group is using an Apple device and iMessage—this is the case if your messages to them appear in blue bubbles—extra features become available when you click or tap the Details button in the upper-right corner of Messages. Did you know that:

• You can give the conversation a name that’s more descriptive than the truncated names of the people in the conversation. On the Mac, type in the Name field at the top; in iOS, tap in Enter a Group Name and then type.
• At any time, you can add more people to the conversation; click Add Member (Mac) or tap Add Contact (iOS) and type the desired phone number or email address.
• You can remove people from the conversation. On the Mac, click the person’s name and press Delete; in iOS, swipe left on a name and tap Delete. Be careful since there’s no opportunity to confirm the deletion, so you’d have to add any mistakenly deleted people back manually. (In iOS, Messages doesn’t always let you remove people.)
• You can even “delete” yourself by clicking or tapping Leave This Conversation at the bottom of the Details screen. Once you’ve left, you can’t get back in without someone else adding you.
• Is leaving a little drastic? Perhaps the conversation is being too chatty while you need to get work done. To mute notifications from the conversation, enable the Do Not Disturb option; disable it when you’re ready to be alerted to new messages again.
• Everyone in the conversation can send or share their location from an iPhone or iPad. Sending a location is like posting a message saying “I’m at the library now” along with a map to where you are. Sharing your location allows the others to see where you are at all times, for one hour, until the end of the day, or indefinitely. Of course, if you opt to share indefinitely, you can revoke that sharing later.
• When anyone in the conversation is sharing their location, a map appears at the top, showing the locations of those who have shared. This is fabulous for keeping track of relatives during family reunions where different groups head out on separate outings.
• Finally, the bottom of the Details screen displays all the pictures that people have shared within the conversation. Messages gives you control over these images, letting you copy, save, open, and delete them. It’s all easy; on the Mac, select photos and Control/right-click to see a contextual menu that includes an Add to Photos Library command or press the Space bar to invoke Quick Look for a bigger view and a Share option. In iOS, touch and hold on a photo to see additional options—tap Save to copy the image to the Photos app.

Alas, if you include even one green-bubble friend who doesn’t have an iPhone with an iMessage account set up and instead relies on plain old SMS text messaging, these features disappear. It’s just another way Apple encourages your friends and relatives to use iPhones.