What is the difference between an Article submission and News submission?

The simple answer is ... there is no difference, except that 'news submissions' will go under the 'news' section and 'article submissions under articles' Each module displays its own contents.

The news module may also utilise different input features like meta keywords that assist search engines, whereas some article modules will have more details about the author etc.

It's up to you to decide how your content will be distributed and which modules provide the best presentation and features.

This Q&A was found on XOOPS Web Application System : https://xoops.org/modules/smartfaq/faq.php?faqid=581