B 

You can highlight certain text and select the B(old) button to cause the text to become darker

 and more pronounced.   

You may also use CTRL+ B on your keyboard to toggle Bold on and off.

I

 If you want to Italicize your text, highlight the text and select the I button.

U 

To Underline your text, highlight the desired text and select the U button.

 abc   

 To give your text a Strikethrough effect, highlight the desired text and select the abc button. 

This icon is handy if you  want to show prices have been slashed. 

 For example:  The price of a book was $12.95 but is now $10!

To remove all of the above type of Formatting from your text,

highlight the desired text and select the  button.

The Undo/Redo buttons will let you recover from accidents while entering text,

such as backspacing over an image and accidentally deleting it. 

The left arrow is Undo or erase my changes.   The right arrow is Redo or go back to the original.

 You may also use your keyboard commands—Ctrl+Z  for Undo, and Ctrl+Y  for Redo.

After highlighting the content you want to Copy, click on the "Control" key on your keyboard.  

 At the same time, click on the "C" key (Ctrl +  C = copy). 

 Move the cursor to where you want the Copy to be placed, and click the  icon.

The copy will be instantly pasted where you placed the cursor.