How do I left align the title of a navigation bar in Xcode?

Well, if you'd like to use large title, then it is left aligned by defaut.

For whole navigation hierarchy.

navigationController?.navigationBar.prefersLargeTitles = true

For 1 viewController

navigationItem.largeTitleDisplayMode = .always

You can use the navigationItems titleView to add a UILabel with left alignment and then set its frame using auto layout like this:

let label = UILabel()
label.text = "Title Label"
label.textAlignment = .left
self.navigationItem.titleView = label
label.translatesAutoresizingMaskIntoConstraints = false
label.superview?.addConstraint(NSLayoutConstraint(item: label, attribute: .centerX, relatedBy: .equal, toItem: label.superview, attribute: .centerX, multiplier: 1, constant: 0))
label.superview?.addConstraint(NSLayoutConstraint(item: label, attribute: .width, relatedBy: .equal, toItem: label.superview, attribute: .width, multiplier: 1, constant: 0))
label.superview?.addConstraint(NSLayoutConstraint(item: label, attribute: .centerY, relatedBy: .equal, toItem: label.superview, attribute: .centerY, multiplier: 1, constant: 0))
label.superview?.addConstraint(NSLayoutConstraint(item: label, attribute: .height, relatedBy: .equal, toItem: label.superview, attribute: .height, multiplier: 1, constant: 0))

let label = UILabel()
label.textColor = UIColor.white
label.text = "TCO_choose_reminder".localized;
self.navigationItem.leftBarButtonItem = UIBarButtonItem.init(customView: label)

I init a UIBarButtonItem with the constructor that gets a UIView and set my desired label as parameter to get the following.

Edit:

If you do not want the back button to be removed. Set the following flag.

self.navigationItem.leftItemsSupplementBackButton = true

Keep in mind that having a label + Back button (with title) would not look cool.In this case I replace the default back button with an arrow asset.