Identifying the correct type of the article is extremely important while submitting your manuscript to a journal which publishes different kinds of study. The classification of studies is broadly based on the content, focus, and implication of the findings of the manuscript.
If you plant to report a study whose sample size, methods, analysis, findings, etc. don't justify a full-length research paper but still contains message or observation of interest to the target audience of the journal, the manuscript can be submitted as a research note or brief communication.
Often, the editor or peer reviewers of a journal provide the suggestion of submitting a thought-provoking study, which falls short of the standard of an original article, as a research note or report in that very journal.
Nevertheless, if you think your study might have a higher chance of receiving favorable peer review report as a short report than as an original article, you can mention this in your cover letter. Once you have clearly explained the merit of your study and how it, as an original article, would interest the readers of the journal, you may add a paragraph in the cover letter proposing the alternative idea.
Here is an example:
"The current manuscript, if published in its entirety in your journal as an original article, will substantially contribute to the current understanding of _____________ (include the name of the topic). Moreover, I believe, disseminating the insights gained from the key findings of this study is important to broaden the perspective of the practitioners in the field and motivate further exploration. Therefore, if required I am willing to restructure the manuscript and present the important observations of the study even in the form of a Research Report or Research Note in your journal.’’
For further readings on different study types in scientific publications, you may refer to