Is there any recognized online portal where anyone can publish articles without being associated with any university or organization? Suppose some working person has interest in physics and mathematics and he want to publish a paper either review or research, so is there anyway he can publish? Obviously person is not associated with any university so he can not name that.
Yes, http://www.arxiv.org is the place for you.

But you can of course also publish in regular journals without being affiliated with a university. Science does not require a formal affiliation, just good ideas and data. If you have the latter, you can publish as a private citizen, an employee of a company, an employee of a government, or with any other background.