This video link Using Google Slides will show you how to export a design from Vectr and create a presentation in Google Slides and how to:
Use text boxes
Change text size and color
Change background color
Insert an image
Maintain hierarchy of design
Watch videos on how to make an Adobe Spark webpage, here are a few: https://www.youtube.com/watch?v=mqT62bdUkk0; https://www.youtube.com/watch?v=2jaSS85UbJU