Hi there!
You can do this with a little bit of custom CSS code.
Go into your site’s admin Dashboard and select Customize → CSS. In the CSS textbox on the left, add the following code:
#actionbar {
display: none;
}
Select “Publish” from the top, and your changes will be applied to your site.
Hope this helps! If you have any further questions, please let us know and we’ll be happy to help. :)