On a computer, it's easy to resize a textarea, like this one:
<textarea>
you just click and drag the thing in the bottom right corner. But on mobile devices, I can't seem to resize the same textarea. Is there something I'm missing? Or do I have to add mobile resizing capabilities separately somehow?
I don't think it can get smaller, modifying rows/cols in CSS doesn't change its look. You can make it bigger though (using above properties), and set it to be dependent on screen size. See:
https://css-tricks.com/snippets/css/media-queries-for-standard-devices/