How to change the message "*!* whispers to you"?

When I type /msg @p xxxxx, it always says *!* whispers to you: xxxx. How do I change this to a name, like xxx: xxxxx, instead?
I'm on the Windows 10 Edition for Xbox One.

Solution 1:

I should've been more specific, I put the commands in command blocks. I don't mind who sees it if it's too much of an issue, but would prefer the person who pressed the button (@p). I'm in a standard creative world.

If the command is in a command block then you need to change the command block name (technically "Hover Note") to what you want it to be. Then when you run the command, it will read:

[ChosenName] whispers to you: {Message}

Additionally, if you only want the person who pressed the button to see it, use @p in the command. After this change, your command will look like this:

/msg @p {Message}