You can send it to a journal that publishes in your area of interest. But first have it looked at by someone who is expert in the field. Alternatively, just make a website and put it online.
Darwin was prompted to publish his theory of evolution by Alfred Russel Wallace. Wallace sent Darwin a manuscript outlining a similar theory of natural selection based on his own research, prompting Darwin to expedite the publication of his own work.
Albert Einstein
james hutton
An early theory describing properties of atoms
1687
1687
You can publish a theory in academic journals, conference proceedings, books, or online platforms that accept submissions related to your field of study. It is important to carefully consider the credibility and relevance of the publication venue before submitting your work.
Jean Piaget published his theory of cognitive development in 1936.
Yes, many self-publish as shareware.
Publish it in a peer-reviewed journal. However, I wouldn't get my hopes up: the fact that you even need to ask indicates pretty strongly that what you've got is probably neither scientific nor a theory.
You can get published either through traditional publishers or self-publish. "Publishing" can be as simple as making pdfs available on your own website.
He knew that the church would oppose his theories.