Content titles are HTML tags used to identify titles and subtitles of your page content. These titles are tagged with H1 to H6 tags (H1 is the biggest title).
The priority is to ensure that the H1 title is defined on your page. Ensure to include main keywords of your page in the title. This will help Google to identify the context of your page more easily.
The size of the title is important: your H1 title must be bigger than the title of your page, in terms of font size. If the H1 title is smaller than the H2 title, Google may take into account the H2 title as the main title.