Within Site settings > Template > Template builder > Header, you can set the position of the Site name or a custom image. 

Advanced options

If the header is displayed, the following Advanced options can be set:

Header top padding
Space above the header

Header bottom padding
Space below the header
Can I add a custom image for my site header?
Yes.  A custom name image can be uploaded in Site settings > Site content > Site name > Custom image tab > Upload image...