There are a number of ways to get formatted text into Blackboard.
There is a new Text Editor that will allow you to format the text within Bb now so you don’t have to prepare it in another program.
If you already have the document in another program, the best thing to do is resave your document as HTML, by going to file, save as web page. Then you can copy and paste the document into Bb.
It would be a good idea to practice with a short document so you know what works best for you.