Now that iOS 11.4 has been released, iPhone owners can enjoy a new feature called Messages in iCloud. This automatically saves iMessages and text messages, including media such as photos, to iCloud. As a result, older messages can be removed from local storage to save space, and everything in the Messages app can be synced across Apple devices.
iOS does offer a quick way to replace your text with emoji - just type out your message and then tap the emoji button. Any word that can be replaced by an emoji will turn orange.
Tap the word to replace it.
You can change the number you're sending to in Messages for OS X simply by clicking on the recipient's name. A drop down menu will let you choose that contact's other numbers.
One of the most highly touted features of Apple's flagship phone, Face ID, is made possible by the iPhone X's new TrueDepth front-facing camera system. It senses features by projecting infrared dots in a known pattern and measuring the distance of each, thereby creating a topographical map of the subject. Rather than using this technology only for security, Apple had some fun with it and created Animoji.
The Messages app on your iPhone can quickly grow to be one of your biggest storage hogs, especially if your friends use it to share a lot of photos with you. If after taking a look at Settings -> General -> iPhone Storage you decide you want to start deleting message threads to free up storage, you probably will want to keep some of the images in those threads.