Based on my research for similar behavior (e.g. Bullet list and Numbered list in UITextView ), I would expect that there is no easy way to do it. I expect that you will have to use textView(_:shouldChangeTextIn:replacementText:)
to hack currently added text to manually add bullets/numbers - e.g., if the user set that she currently wants to use unordered list, you will have to detect a new line added in shouldChangeTextIn
and manually add there the bullet and indentation.
Another approach which you might consider (its applicability depends on your requirements) is to customize existing open source rich text editor. In my case I was able to get close enough to what I needed using RichEditorView, which uses HTML+CSS as an underlying technology (so to be able to do customizations, you need to know a bit about JavaScript, CSS and HTML).