What is a magazine paper and how it is different from a journal paper
IEEE magazine articles are aimed at a more general audience than conference or journal papers, which are usually aimed at a small group of specialists in a narrow subfield. 

They can be a way to expose the author's technical work to a broader audience, give an overview of an area, or present something that is of interest to researchers in the area but isn't appropriate for a technical journal article (for example, to explain the legal, economic, or political issues behind a particular research area).

Because they serve a different purpose from "regular" journal articles, manuscripts submitted to magazines are judged according to some additional magazine-specific criteria. For example, the peer review form for one IEEE magazine I reviewed for included the following specific questions:


  
  Is the paper understandable to a general ComSoc audience with minimum mathematical content?
  Does the paper format conform to magazine guidelines (max. 4500 words, 6 figures/tables, 15 references)?
  


in addition to more "usual" ones:


  
  Is the paper topic important and interesting to the magazine's readership?
  Is the paper technically sound?
  Does the paper discuss novel and original work?
  How is the presentation and organization of the paper?
  


A note on those "magazine guidelines": Because IEEE magazines do not publish specialized and detailed technical papers, they often have limits on the number of equations, figures, and references that authors may include. For example, from the guidelines for IEEE Communications Magazine:


  
  Articles should be tutorial in nature and should be written in a style comprehensible to readers outside the specialty of the article.
  Mathematical equations should not be used. In justified cases up to three simple equations could be allowed, provided you have the consent of the Guest Editor. The inclusion of more than three equations requires permission from the Editor-in-Chief.
  References should be included only to guide readers to more information on the topic; the reference list should not include every available source. A limit of 15 references is recommended. The inclusion of more than 15 references requires permission from the Editor-in-Chief. References to Web pages should be checked immediately for accessibility before submitting material to the Production Staff.
  Figures and tables should be limited to a combined total of six.
  


If the paper you want to write needs more equations, references, figures, or tables than the magazine guidelines allow, this may be an indication that it's too technical for a magazine article, and is more suitable for publication in a regular journal.

Regarding your other questions:


  I am also wondering, can a PhD student be a first author in a manuscript submitted to a magazine or the first author has to be famous in the field in order to be trusted by the reviewers.


Yes, a PhD student can be a first author on a magazine paper. I have a first-author magazine paper; I am a PhD student, and I am not famous :)


  Last question is if a PhD student graduates with one magazine paper will that help to get a faculty position or it is counted as a journal paper.


Magazine papers are nice because a good magazine article can rack up a lot of citations. For example, in my field of computer networks and wireless communications, IEEE Communications Magazine has the highest h-index. Similarly, IEEE Signal Processing Magazine, IEEE Industrial Electronics Magazine, IEEE Communications Magazine, and IEEE Wireless Communications Magazine are included among the top IEEE journals in terms of impact factor. 

But a magazine paper won't be considered the same as a journal paper, because it lacks the technical depth of a journal paper.