If you can read words and write words, you have most of the skills you need to be a writer Writing classes help, of course, and so do books on writing, and lots of practice. But there's no real mystery to things: writers write.
The basic tools you need to be a writer are:
Usually you write on paper, but you could just as easily write on the back of your hand, as long as you don't wash it. And there are many, many things with which you might do the actual writing: you could use a pen or pencil or crayon or lipstick or a piece of charcoal or a particularly dirty stick. Some of these are more permanent than others, so you may want to consider sticking with the more typical writing implements. Or, you could decide to avoid the use of handwriting altogether and go straight for typing, either on a computer or on a clackety typewriter.
It you really want to be a writer, here's what I suggest:
That's right, you heard it here. In order to be a writer, the only thing required is to actually write something, whether it be poetry or stories or letters or newspaper columns.