Users who are fully invested in Apple’s ecosystem—you use Macs, iPhone, iPads, etc.—have noticed for a while that some apps that you can use on all platforms don’t always have the same features. Messages is a prime example of that. The iOS and iPadOS versions have had features you won’t find on macOS.
That’s changed with macOS Big Sur. Apple used its Mac Catalyst technology to convert the iOS version of Messages to a version for the Mac. The result is that the Mac’s instant messaging app is more robust and works just like it does on the iPhone and iPad.
Here’s an overview of Messages in Big Sur.
More tools to write messages
Apple made a ton of improvements to the tools you use to create a message. There is a new icon located to the left of the text box when you write a message. Click it, and you can select from Photos (pictures in the library of the Photos app), Memoji Stickers, #images (which brings up a searchable library of gifs), and Message Effects.
Your name and photo or Memoji can be set to automatically share with the person you’re communicating with, whether that person is in your contact list or not. Speaking of Memoji, Apple will provide a Memoji editor so you can customize your look, and the new Memoji stickers can be used to graphically communicate a feeling or idea.

New tools for creating messages.
Better search
Messages now has improved search to make it easier to find what you are looking for in your message list. Search results are grouped into Conversations with the search term highlighted, and sections for Links (website URLs), and Photos.
Message organization
You can pin up to nine conversations at the top of your list, and your pins appear on your iPhone and iPad, too. To pin a conversation, right-click on it in the message listing, and then select Pin. To unpin a conversation, right-click it and select Unpin.
In a group conversation, you’ll be able to reply to a specific message to maintain context; you don’t have to worry about your response being out of the flow. You can also type a name to direct a message to that particular person. And you can assign an image to a group conversation, which helps it stand out in your listing.