How to add left and right margins to a UITextView...

uitextview-margin.m

float padding = 10.0;

NSMutableParagraphStyle *editorParagraphStyle = [NSMutableParagraphStyle new];
[editorParagraphStyle setHeadIndent:padding];
[editorParagraphStyle setFirstLineHeadIndent:padding];
[editorParagraphStyle setTailIndent:-padding];

NSDictionary *textAttributes = @{
    NSFontAttributeName: [UIFont fontWithName:@"Helvetica" size:14],
    NSParagraphStyleAttributeName: editorParagraphStyle
};

[self.textView setAttributedText:[[NSAttributedString alloc] initWithString:self.textView.text
                                                                 attributes:textAttributes]];