How do you change the colour of a section title in a tableview?

you can use the one of UITableViewDelegate's method

swift3 and above

  func tableView(_ tableView: UITableView, willDisplayHeaderView view: UIView, forSection section: Int) {
    if let headerView = view as? UITableViewHeaderFooterView {
        headerView.contentView.backgroundColor = .white
        headerView.backgroundView?.backgroundColor = .black
        headerView.textLabel?.textColor = .red
    }
}

objective C

- (void)tableView:(UITableView *)tableView willDisplayHeaderView:(UIView *)view forSection:(NSInteger)section
{
    if([view isKindOfClass:[UITableViewHeaderFooterView class]]){
        UITableViewHeaderFooterView * headerView = (UITableViewHeaderFooterView *) view;
        headerView.textLabel.textColor  = [UIColor RedColor];  
    }
}

for Reference I taken the model answer from here

Custom Title:

override func tableView(tableView: UITableView, willDisplayHeaderView view: UIView, forSection section: Int) {
    let title = UILabel()
    title.font = UIFont(name: "SFUIDisplay-Light", size: 13)!
    title.textColor = UIColor.redColor()

    let header = view as! UITableViewHeaderFooterView
    header.textLabel!.font=title.font
    header.textLabel!.textColor=title.textColor
    header.contentView.backgroundColor = UIColor.whiteColor()
}

One liner solution (using optional chaining):

override func tableView(_ tableView: UITableView, willDisplayHeaderView view: UIView, forSection section: Int) {
    (view as? UITableViewHeaderFooterView)?.textLabel?.textColor = UIColor.red
}