Many apps that you downloaded from the App Store are compatible with the Messages app. For example, if you have Words with Friends, you can play that against a friend within the Messages app. To enable it you have to go to the iMessage App Store by opening any conversation in Messages and tapping the "A" button to the left of the text box. Then tap the four oval icon in the bottom left, then the blue "+" Store button. Now tap the "Manage" tab and you will see all of your apps that are compatible with Messages. Toggle on the ones you want to use.
To get to the iMessage App Store, open up the Messages app and open a conversation. To the left of the text box you will see and icon that resembles an "A." Tap on that, then tap on the four oval icon in the bottom left. Now you will see a blue "+" icon, which is the store. Tap on it to go to the store.
Whenever you sell, donate, return to your employer or otherwise decommission an old Mac, it is of utmost importance to clean your private data from it. If you have set up your Messages app it would be wise to delete your Apple ID account from it rather than simply logging out of it. Unfortunately (and amazingly) this is frustratingly difficult to do - you can't just highlight the account and delete it for some odd reason. There is, however, a roundabout way to get the job done; here's how to do it:
Among the many new features introduced by iOS 10 is the integration of apps with the Messages app. While sticker packs were probably one of the first Messages apps you became aware of, there are many more. ESPN lets you send score updates to friends, OpenTable lets you and your friends vote on where to eat, Yelp lets you share reviews, just to name a few. In fact, many of the apps you use regularly may integrate with Messages. Here's how to manage them within Messages:
This feature, known as "Tapback," is available in macOS Sierra. Simply right click on a message you want to add an effect to and select Tapback. Your choices will appear; click on the one you want to send.