The MainWP Article Uploader Extension allows you to upload multiple articles to your child sites. You are given the option to upload separate TXT files or to import them using a custom formatted CSV file.
The Upload Articles section allows you to upload multiple text files (.txt) containing only a title and content for an article. After uploading the articles, the Extension then gives you the options to publish articles immediately as a post or a page, set the category and allow/disallow comments.
A more powerful method that allows you to import multiple articles in one or more TXT or CSV files. This method also enables you to set not only article Title and Body, but also article Slug, Categories, Tags, Excerpt, Author…