The "Header Only" is a sub-part of all "Typical Page Contents" so you can define your Header styles there. Hoewever sometimes you will need only a header. In that case you can use "Header Only"
Type: Here you will find all default header styles (H1 - H5) and probably some variants that are specific to your Website
Alignmet: You can set it to left, center or right
Date: If set it will be rendered above the header (not implemented)
Link: you can link the header to a page
Subheader: The Subheader position might be below or above the header, it depends on the layout of your Website
Header 1
Header 2
with sub header
Header 3
with sub header
Header 3 with link
with sub header
Header 3 centered
with sub header