How do I turn on dark mode on Telegram?

A lot of apps have a dark mode for low light viewing, how do I use Telegram's night mode?

Many popular apps including Reddit, Twitter, Youtube, the iPhone itself and more offer a dark mode that makes viewing the screen in little or no light situations easier on the eyes (and less distracting to others). The popular messaging app Telegram is no exception. To turn on Telegram's dark mode, head to Settings -> Appearance and choose Night Blue or Night under Color Theme.

How to turn on dark / night mode for Telegram on iPhone and iPad.