Of course -- that's where almost all of them were made. But that doesn't solve your problem. If you're talking about emojis (e.g, yellow happy/sad faces), those are funneled through a standards organization, so that MacOS, Windows, iOS, Android, and Linux share the identity of a given emoji code. Though the precise look of a happy face may differ between platforms, the computer code for happy face should display a happy face on every platform Emojis are only created by the platform vendors. Instructions for choosing an emoji are here.
If you're talking about things like the red Q pill you use as part of your signature, there are ways for users to create them. The common but expensive tools for this are Adobe Photoshop and Adobe Illustrator. Photoshop is excellent for photos. For example, if you found an image of a red pill on the internet, you could erase its background, produce a shadow effect, superimpose text on it -- as TXnMA (was it?) did. Illustrator, a graphics editor, would allow you to create such a pill from scratch.
Both of these tools are pretty expensive, however. Fortunately there are free tools that come pretty close. For photo editing, GIMP is a pretty good approximation to Photoshop. Although I haven't really used it myself, Inkscape appears to be a pretty good graphics editor. Both of these are free.
After all that, what did you have in mind?
Just the little emojis like other people use. haffast posted a youtube instructional and it was easy enough for me to figure out. I am now a master of emoji style gung fu.
Next, I will check out GIMP, which I've heard of so I can make my own graphics.
The road to nerd-dom goes ever on, as Tolkein once said. I think.
Thank you for the tips, goodman.
Bagster