You can use this example and change it's implementation like this:
[self enumerateAttribute:NSParagraphStyleAttributeName
inRange:NSMakeRange(0, self.length)
options:0
usingBlock:^(id _Nullable value, NSRange range, BOOL * _Nonnull stop) {
NSMutableParagraphStyle *paragraphStyle = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
//add your specific settings for paragraph
//...
//...
[self removeAttribute:NSParagraphStyleAttributeName range:range];
[self addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:range];
}];