This is the option available on site globally from the Site Editor, i.e. not present in the post/page editing. The style you apply will reflect all the post titles on the template you’re editing.
You’ll have the option to use the “Highlight” style, just like it’s available with headings:
The default title no style applied
The title with the accent small 1
The title with the accent small 2
The title with the accent huge 1
The title with the accent huge 2
The title with the underline and overline
The title with the aside lines
The title with mixed colors
The title with mixed colors light
The title with colors center-focused
The title with a transit to a lighter color
The title with an asterisk
The title with a star