I heard that community college credits are not accepted at universities, is this true?

No.  Most credits at MCC are specifically designed so they can be transferred easily to a partner university.

How do I know what classes at MCC to take which will go toward my Bachelor’s degree at a university or college?

Each degree has different requirements at different universities.  Research that degree’s course requirements to learn what to take.  Such course requirements can likely be found on the university's website.  If you are planning on attending a public Arizona university, check out aztransfer.com for course equivalencies, math and language requirements by major and more.

What requirements, when transferring credits to MCC, determine awarded MCC credit?

You must earn the equivalent of a “C” in the class, or a 2.0 on a 4.0 scale, to attain MCC credit. The credits must also be from a college level course taken at an accredited school to qualify.  In addition, no more than 30 credit hours may be transferred for MCC credit.