On #iOS Text Replacement is a really useful feature in iOS and works on Mac OS also, what you do is go to Settings>General>Keyboard and setup shortcuts under Text Replacement settings.
This is really helpful for people who type a lot as they can create shortcuts to frequently used terms, I like to use it for stuff like ty to thank you, gn to goodnight, yw to you're welcome.
But you can go a step further and setup really long things like home address or info about someone just to a couple of letters. Really helpful if you communicate information on a daily basis like links, addresses, bank info, custom template messages.
Lastly if you sync up your devices the shortcuts will work on your Mac OS device also making emails so much easier than you would think.