It really depends upon the denomination. Here are a few tidbits of info:
The MDiv degree does not automatically confer ordination. The school confers the degree, but the church confers the ordination.
Most denominations require an MDiv for ordination. Mine requires the MDiv with some specific academic requirements in addition to the ordinary degree requirements. There are also ordination exams and other elements of the process, but that's the academic component.
The MDiv is considered a three-year degree (in addition to the bachelor's degree you earn in college), although I know a number of people who do it in four years, so as to do internships or just maintain sanity.
There are seminaries associated with particular denominations and ones that are intentionally multi-denominational. There are advantages to choosing either one, so it's best to speak to someone in your denomination to get guidance on what is needed in your case.
In the congregational form of polity (found most generally in baptist, pentecostal, or non-denominational churches), the individual congregation has most, if not all, of the "say" as to what is required for ordination. If this is your tradition, then I recommend speaking to your pastor about the possibilities.