While working in a Post or Page, you can do basic text editing. You can select these features in the toolbar located directly above the keyboard to make changes to your post as you type, including bold, italics, hyperlink, blockquote, and bulleted or numbered lists.
You can also switch to HTML mode for more advanced text editing. For example, you can add a "Read More" tag to your posts by pasting this in HTML mode:
To get into the HTML mode, tap the icon that looks like </>. Tap it again to get back to the Visual editor.