To highlight text in your eBook on the VitalSource Bookshelf App, follow the steps below:

Online BookShelf App
Click and drag your cursor until you have the desired area of text selected.
Upon releasing the mouse a pop-up box will display that will allow you to select your highlighter color and add a sticky note.
Highlights can be copied and pasted into an external program.

Desktop BookShelf App
Click and drag your cursor until you have the text selected.
Select the highlighter color from the drop-down menu at the top of the screen.
Choose to just make a ‘Highlight’ or ‘Highlight with Note’.
Right-clicking highlights allows you to export or copy them and any attached notes.

Mobile BookShelf
Long press the text to begin highlighting.
Use the grabbers at the beginning and end of the selected area to make adjustments.
With the desired area selected tap ‘Make Highlight’ and your highlight will be made in the color you last used.
To change this color tap the highlighted area, select ‘Highlighter’ and your new color.