How do I add a subscription button (RSS? , others) ?

Sorry for the newbie question. but how to I add a very easy way for people to subscribe to my blog? (I’m using the online web version of wordpress – did not download it, or incorporate it into a website)

I at least want to make if easy for people to subscribe to receive posts via email. but also other methods.

I thought this would be automagically built-in, but I didn’t see a way to do this.

thanks!!