In the bottom left corner, there is a search box. Type in the name of the program you want to add to the taskbar in this box. In this example, I will use Discord but you could just as easily use this for any other program like Word.
Once you start typing in that box it will start to narrow down until you find what you are looking for.
You will now have that program on your lower taskbar and just one click away from launching instead of two clicks like on your desktop.
As you will now see, the icon will stay at the bottom even when it is not being used. This method is easier than having the icon on the desktop since it is always there even if the desktop is not showing and only one click. This is best used for programs you use often.