Go to Settings > Ease of Access > Keyboard or just press the windows key and begin typing "keyboard" and press enter when you see a shortcut for on-screen appear in the search results.
The first switch at the top will toggle the on-screen keyboard.
Also, Windows often puts a button in the far right corner of the taskbar near the clock that toggles the on-screen keyboard. Its possible that you clicked this button by mistake. To remove it, right click anywhere on the task bar and uncheck the option for "Show touch keyboard button."
Your question is much too broad - Windows contains many Microsoft applications,
but you most probably have also installed some third-party applications.
The integration between all these applications is usually non-existent,
so the problem of emojis is better analyzed in the context of the applications
in which you would like to use them.
If you would like to use the emojis in writing, this means using the corresponding
Mac font on Windows. You could use for that one of the following tools :
DfontSplitter
(description),
Macdisk,
Fondu.
However, even if you ported these fonts to your computer under Windows,
they will still only exist on your computer.
If you would wish to use them for communicating with other people,
you would need to include them in the sent document.
Embedding fonts is possible for Word documents or PowerPoint presentations
(see article),
and is also possible for PDF documents
(see documentation),
but only for very few others.
If you are looking for a general solution for using everywhere,
the only one I can think of is to take images of the emojis and use them
in your communications. This is the only general and portable
solution I can think of.
If you are looking for a better solution for use in a specific application,
let us know which application and we will try to help.
However, for many applications the only solution would be that
of using images of the emojis.
Best Answer
There's a setting for this: