Suppose that we have the following document:
\documentclass{article}
\begin{document}
\cite{article-crossref} and \cite{article-full}.
\bibliographystyle{plain}
\bibliography{xampl}
\end{document}
Now, we compile in the usual way, using our editor of choice or on the command line or whatever. We make sure that everything is properly resolved and defined, running the compilation sequence multiple times if needed. (Compilation is just running e.g. pdflatex -> bibtex -> pdflatex -> pdflatex.)

Now, to prepare the file for journal submission, we open the .bbl file, which will be in the working directory, by default, or wherever you've asked for generated files to go.
Here's mine:
\newcommand{\noopsort}[1]{} \newcommand{\printfirst}[2]{#1}
\newcommand{\singleletter}[1]{#1} \newcommand{\switchargs}[2]{#2#1}
\begin{thebibliography}{1}
\bibitem{article-crossref}
L[eslie]~A. Aamport.
\newblock The gnats and gnus document preparation system.
\newblock {\em \mbox{G-Animal's} Journal}, 41(7):73+, July 1986.
\newblock This is a cross-referencing ARTICLE entry.
\bibitem{article-full}
L[eslie]~A. Aamport.
\newblock The gnats and gnus document preparation system.
\newblock {\em \mbox{G-Animal's} Journal}, 41(7):73+, July 1986.
\newblock This is a full ARTICLE entry.
\end{thebibliography}
We copy this into our original .tex file at the point where we issued the \bibliographystyle and bibliography commands:
\documentclass{article}
\begin{document}
\cite{article-crossref} and \cite{article-full}.
\newcommand{\noopsort}[1]{} \newcommand{\printfirst}[2]{#1}
\newcommand{\singleletter}[1]{#1} \newcommand{\switchargs}[2]{#2#1}
\begin{thebibliography}{1}
\bibitem{article-crossref}
L[eslie]~A. Aamport.
\newblock The gnats and gnus document preparation system.
\newblock {\em \mbox{G-Animal's} Journal}, 41(7):73+, July 1986.
\newblock This is a cross-referencing ARTICLE entry.
\bibitem{article-full}
L[eslie]~A. Aamport.
\newblock The gnats and gnus document preparation system.
\newblock {\em \mbox{G-Animal's} Journal}, 41(7):73+, July 1986.
\newblock This is a full ARTICLE entry.
\end{thebibliography}
\end{document}
Now clean to remove the generated files, so you are sure you aren't still relying on the external .bbl and re-compile at least twice (pdflatex -> pdflatex) to obtain the same result from just your .tex file.
.bblfile should not be written by you (you can tweak it manually, but you shouldn't because your changes will get written over whenever you produce a new revision), it is produced by thebibtexprogram. You have to runbibtexon the.auxfile produced bypdflatex– Au101 Feb 01 '17 at 00:45.bblfile appears after you've runbibtex, it is produced by thebibtexprogram, not by you. How is probably not worth going into, but it uses your.bibfile, the.auxfile and any.bst(style files) you've requested. You will find it in the same folder as your.texfile along with the.logthe.auxand other such files thatpdflatexproduces, unless your system is configured to put those files somewhere else so that they don't clutter up your folders, in which case, we need to know more about your system – Au101 Feb 01 '17 at 00:47.bblfile will be in your working directory after you've runbibtex. Open it, copy the contents into athebibliographyenvironment in the place where you had\bibliographystyle{<style>}\bibliography{<bibfile>}. – cfr Feb 01 '17 at 00:48thebibliographyenvironment. I don't mean to add another one. See my example below. – cfr Feb 01 '17 at 01:02