They allow for users to create text sections that are personalized and unique, rather than just words. Some of these customizable features include the ability to insert images, change the font, change text color, add numbered or bulleted lists, and more!
The best way to use these text boxes is to treat them as if they were a word document. They basically work the same way. Therefore, to make the most out of you WYSIWYG boxes, treat them like miniature word documents!
One tip though is to copy and paste using the keystroke shortcuts. This eliminates any problems with adding information.
Windows: ctrl, shift, C/P
Mac: command, shift, C/P
Also, if you want to add an image to the WYSIWYG box, make sure the image in added to your image library. Note: it DOES NOT have to be in .png format