Writing a draft
The purpose of publishing your research is to provide access to others; enable them to assess your findings, repeat the experiment or process, and to determine whether your conclusions are true.
The basic structure of a paper is summarised by the acronym IMRAD, which stands for
Read more about writing a paper in "How to write a paper" edited by George M. Hall.
Follow the journal author guidelines
It's important to stick to the specific "guide for authors" of the journal you are submitting to. This can be found on the journal's home page and will usually include the editorial policy and guidelines to authors as well as any other relevant information required for you to meet the standard required for acceptance.
Submit your paper
You will need to submit your paper according to the journal's instructions. Some publishes accept email and post submissions whilst others may have an online system. There may be different requirements or rules, for example; how many copies, how to prepare data in figures and tables, whether supplementary information is required or who will sign the cover letter if there are multiple authors.
Once submitted, you will need to await the editorial feedback for your paper.