Click Details at the top-right of a conversation to activate Do Not Disturb for that thread alone. This setting persists until you return to the conversation and turn it off. You can tell who is muted, as you will see a moon icon to their left in Messages’ main window. Click Details at the top-right of an iMessage conversation and, next to the phone and video icons, you’ll see an icon that resembles two overlapping rectangles. Click it to find options for sharing your screen with the contact, and to request to see their screen – handy for helping out with technical problems. Messages’Video menu includes three items at the bottom that determine what communication methods are active. You can disable screen sharing, video chats and audio chats if you like, and stick to text messages. Written words don’t always express exactly what we want to say, but in Yosemite you can really make yourself heard. Just like on your iPhone and iPad in iOS 8, you’ll see a microphone icon next to the compose field when sending an iMessage. Click it and you’ll start recording an audio message. Press Space once to stop recording, and again to send the soundbite. Once you get used to this you'll probably wonder why you bother with text-only messages! Call forwarding is a nice modern convenience, but perhaps you don’t want to receive phone calls on your Mac, or else only on some of your devices in addition to your iPhone (we now exactly what it's like to have all your devices going off at once!) Under Settings in FaceTime’s preferences, the checkbox labelled ‘iPhone Cellular Calls’ determines whether calls will come through to the Mac you’re using. On your iPad or iPod touch, the same option is found in Settings > FaceTime. You will of course have to be running iOS 8. When our iPhones are in our pockets, we rarely miss a call, but when we’re working at our desks we don’t always hear it buzzing. Yosemite understands this predicament. A notification banner will alert you when a call is coming in on your iPhone, and you can answer it right on your Mac. And you can make calls, too; simply click a number in Contacts or Safari and it will start dialing.
In order, for phone calls to work on your Mac, your iPhone will need to be running iOS 8 (or 8.1 if you also want to see SMS texts in the Messages app). Naturally, both your Mac and your iPhone need to be signed into the same iCloud account, and they must both be connected to the same Wi-Fi network, too. Messages no longer allows fancy customisations for the fonts and colours of its message bubbles (a loss for some), but it does include a new slider for setting a persistent size at which to present things in the iMessages window. There are now seven options to choose from, which can found in its preferences under General.