I display html in UITextView by:
[self.textView setValue:@\"Content\" forKey:@\"contentToHTMLString\"];,
After edit
According to Display html text in uitextview this question Use a UIWebView.
Because undocumented -[UITextView setContentToHTMLString:] method. App will be rejected for using undocumented methods.
But still you want doing this you can take a look this links Might be help:-
https://github.com/AliSoftware/OHAttributedLabel
https://www.cocoacontrols.com/controls/bctextview
https://www.cocoacontrols.com/controls/egotextview
and for doing this task with UIWebview you must look this :-
Rich-text-editing-sample-project