how can I change line to paragraph in sublime?

It's more like a superuser question, but with the multiline editing it can be easily done in Sublime: https://www.youtube.com/watch?v=WXuBgSpLpK4

Just select all the paragraphs, press cmd+shift+l, to place a cursor at the end of every line, then you can put </p> there.

The next step is to jump to the beginning of the lines by pressing cmd+'<-' (left arrow key) and put <p> there.