Messages on Apple Watch is one of my most used apps. I love being able to quickly read and reply to new messages. Apple Watch does its best, based on the content of the message, to offer you some quick replies. If someone asks me a question, it might list Yes, No, and then the default replies that come with Apple Watch. Using Apple Watch for iPhone, you can customize this list.
Go to Apple Watch.app → Messages → Default Replies (requires iOS 8.2 or later). You can override the built in replies to have your own list. I use a handful of emojis and common replies. You can also use this list when composing a new message. I’d love to see this listed expanded to include more slots in future versions of Apple’s Watch OS.
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