It's commonly known that you can use code formatting by surrounding your code with backticks:
`enter code here`.
` character is fairly well hidden on the default iOS keyboard, making it inconvenient at best, or impossible to find at worst.
This isn't an issue when writing questions or answers, since there's a convenient "insert code button", but unfortunately there's no such button when writing comments.
There should be an alternative way of enclosing code on mobile devices, such as a code formatting button when writing comments.