Is there any built-in feature Kentico 13 to export list of articles(pages) as word or pdf ?

There is not.

I'd suggest using the browser print functionality along with a print stylesheet and print your page to PDF.

Is there any feature for sending list of articles via email? I just need to send list of articles to be imported into another system or to be translated so need to download list of articles or send it by email? when i use the translation service the XLF file contains only the body but doesn't contain the content That needs to be custom implementation?

For that, I'd suggest querying the database directly.