Customize UITableView header section

You can try this:

 -(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
    UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, tableView.frame.size.width, 18)];
    /* Create custom view to display section header... */
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(10, 5, tableView.frame.size.width, 18)];
    [label setFont:[UIFont boldSystemFontOfSize:12]];
     NSString *string =[list objectAtIndex:section];
    /* Section header is in 0th index... */
    [label setText:string];
    [view addSubview:label];
    [view setBackgroundColor:[UIColor colorWithRed:166/255.0 green:177/255.0 blue:186/255.0 alpha:1.0]]; //your background color...
    return view;
}

The selected answer using tableView :viewForHeaderInSection: is correct.

Just to share a tip here.

If you are using storyboard/xib, then you could create another prototype cell and use it for your "section cell". The code to configure the header is similar to how you configure for row cells.

- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
    static NSString *HeaderCellIdentifier = @"Header";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:HeaderCellIdentifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:HeaderCellIdentifier];
    }

    // Configure the cell title etc
    [self configureHeaderCell:cell inSection:section];

    return cell;
}

Swift version of Lochana Tejas answer:

override func tableView(tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
    let view = UIView(frame: CGRectMake(0, 0, tableView.frame.size.width, 18))
    let label = UILabel(frame: CGRectMake(10, 5, tableView.frame.size.width, 18))
    label.font = UIFont.systemFontOfSize(14)
    label.text = list.objectAtIndex(indexPath.row) as! String
    view.addSubview(label)
    view.backgroundColor = UIColor.grayColor() // Set your background color

    return view
}

If you use default header view you can only change the text on it with

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section

For Swift:

override func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {

If you want to customize the view you need to create a new one your self.

why not use UITableViewHeaderFooterView?