Because two of my interviewees speak in Spanish. I have to put subtitles in English. Before, I have been researching about it and I have found in Channel 4 website, the type of font and the size. In that website, they give some guidelines about how to add subtitles in your project. For example, All subtitles must stay within text safe areas or the maximum two lines of text per subtitle. Where two lines are used, both should be of roughly equal length with the top line the longer.