Download Pdf from Url on button click In Objective-C

Question

I have to download a pdf from url on a button click in Objective-C

This is what I have done:

- (IBAction)DownLoadPdfButton:(UIButton *)sender {
    
   NSString *currentURL = @"http://africau.edu/images/default/sample.pdf";
            NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:currentURL]];

            NSURLConnection *conn = [[NSURLConnection alloc] init];
        (void)[conn initWithRequest:request delegate:self];

        dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0ul);
        dispatch_async(queue, ^{
           NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:currentURL]];
            dispatch_sync(dispatch_get_main_queue(), ^{
            });
           NSString *resourceDocPath = [[NSString alloc] initWithString:[[[[NSBundle mainBundle]  resourcePath] stringByDeletingLastPathComponent] stringByAppendingPathComponent:@"Documents"]];

           NSString *filePath = [resourceDocPath stringByAppendingPathComponent:@"myPDF.pdf"];
            [data writeToFile:filePath atomically:YES];
        });
    
}

I don't want to declare any path for saving my pdf.. please provide answer only for downloading pdf on button click and if pdf is not downloading then show error on console.

I have refered other answers.. but they are not useful.