A great place to go for many citation and quotation questions is the Purdue OWL. On their MLA guide, it specifically breaks down examples for how to go about citing and using varying resources. Here's their page that includes information regarding personal interviews: https://owl.english.purdue.edu/owl/resource/747/09/
And here's what they say:
"Personal interviews refer to those interviews that you conduct yourself. List the interview by the name of the interviewee. Include the descriptor Personal interview and the date of the interview.
Smith, Jane. Personal interview. 19 May 2014."
This refers to the citation on the Works Cited page. For quoting in-text, you would then follow the standard MLA way of quoting and citing in-text, which means unless you mention the interviewee's name in the sentence you would put their last name in parenthesis at the end of the sentence. What you put in parenthesis in-text in MLA should correspond to the first part of your citation on the works cited page. In the previous example your in text citation would be (Smith) unless you referred to the interviewee by name in the sentence.
Plan the outline of your interview essay based on the ordering of your reasons.
Introduction/Conclusion: Decide how you will begin and conclude your essay. Your introduction should include the question you asked. Your opening might be suggested by some of the comments from your interviews or you might want to describe a situation which causes your question. For example, in a paper about whether you would give money to a homeless person, you could open with a scenario or story about being approached by a woman in a parking lot and having to decide whether to give money. You might also use description, statistics, and/or questions in your opening (describe homeless people in a big city, give statistics, and end with the question you asked in your interview). You could also begin with a dictionary definition, an appropriate reference to a movie, T.V. show, or song, or a quote.
Body: List the reasons in order. The body of your essay should follow the order of reasons that you put together from your notes. Be sure to quote, paraphrase, and summarize your sources. Also be sure to analyze the connections between reasons and why people might come to those conclusions.
Conclusion: Your response. You will conclude the paper with a paragraph or two explaining which point-of-view, in your opinion, has the most validity, and why. If none of the viewpoints from your interviews coincided with your opinion, you should talk about that.