Aspire, this is a topic where it can be easy to be lost in the 'grey'. So I have included a short excerpt from another source that outlines fairly succinctly what you can and can't do when converting an article.
"Additionally, a thesis and a journal article are completely different in terms of overall approach and format. To convert a thesis/dissertation into a journal article, it has to be rewritten and refined. More often, a journal article is crafted based on an excerpt or a chapter of a thesis, and sometimes, multiple articles can be published based on different thesis chapters. The journal article undergoes further revisions during peer review, which makes it substantially different from the thesis, thus solving the problem of duplication. Charges of self-plagiarism can be avoided by citing the thesis/dissertation in the journal paper, and using block quotes wherever content has been copied verbatim.
\Most importantly, you should inform the editor at the time of submission that your article is based on your thesis, mention when and where it has been published, and state your willingness to provide a copy if required."(Editage Insights).