Hello , is it negative for SEO to have the same articles in Pages and Posts on the same site? Should a piece of content be only in Pages or Posts? Is it a duplicate issue to be in both? thanks
If you want user comments, use posts. If you need to post static content (about, contact, terms, privacy policy), use pages. Duplicate content under two different URLs is bad.
First way is try to avoid this type of duplicate work because on same domain your work will be useless because search engines will ignore either page or post. If many duplicate then can reason of any warning (Not sure but may be.) Second way is use canonical tag for duplicate page or post. By this way you can say search engines that this page or post is canonical (means duplicate) of this page or post. Ease for search engines and your work is also in safe mode.
If you are looking forward to provide the courses to the people who want to know more about the digital marketing, then one can go ahead and market your course online as per the wish and convenience.