Two of all elements are mainly responsible for text content, they are: Heading and Text.
Although they are very similar, in practice you should use Heading for title, subtitle, dividing content layout, and Text for long content.
Beside settings from Sidebar, both of them support text inline formating for extra flexibility.
You can format a part of the text by select it, a format popup will display right next to it. You can then make it bold, italic, underlined, insert link, superscript or upperscript.
The inline style should be used for a part of text only and will override element styles being set from Sidebar.