stringByAddingPercentEscapesUsingEncoding was deprecated in 9.0 .How to do this?

If you want just fast example look at this code:

NSString * encodedString = [@"string to encode" stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLFragmentAllowedCharacterSet]];

Also check List of predefined characters sets

If you want explanation read the documents or at least this topic: How to encode a URL in Swift