// date from string

NSString *dateString = [NSString stringWithFormat:@"%@",_model.time]; // model.time is the field in which we are fetching the string.
   
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ssZZZZ"];
    NSDate *dateFromString = [[NSDate alloc] init];
    dateFromString = [dateFormatter dateFromString:dateString];
   

  // string from date

NSDateFormatter *dateFormatter1 = [[NSDateFormatter alloc] init];
    [dateFormatter1 setDateFormat:@"dd-MMM-yyyy"];  // format in which we want our date to display
    NSString *stringOfDate = [dateFormatter1 stringFromDate:dateFromString];
    NSLog(@"%@", stringOfDate);

Hello all !!
Suppose we are fetching some data from the server through API Hit and in that we have one field having date and time both ( in string type) within it. Now what we want is to get only date from that string and not the time. So we have  to convert it from NSString to NSDate to get the desired result (we have to convert it again into NSString )..
Then we can use this code to implement this !!