The Master Journal List - Clarivate Analytics is part of the Thomson Reuters website and it is mentioned on the webpage that "The Master Journal List includes all journal titles covered in Web of Science." It is not mentioned anywhere that these journals are the ones applying for indexing. However, if you want to be doubly sure, you can also check the list of journals in the 2016 release of the Journal Citation Reports (JCR). This is the official list of journals released by Thomson Reuters in 2016.
First of all, I would like to thank you for the information you are providing to beginner researchers like me. It helps us a lot. I have an article to be published in a journal listed in the master list of journals indexed in Thomson Reuters. I have already paid the publication fee. Somebody told me that the journals listed in the "Master Journal List - Clarivate Analytics" are not the journals indexed in Thomson Reuters but instead applicants for indexing, and that there is another official list of journals indexed in Thomson Reuters." On that Master Journal Lists-Clarivate Analytics, I found the name of the journal where my article is to be published. Additionally, I saw a list of searchable databases. When I clicked on the subject area that my article belongs to, the name of the journal appeared. Is there other way to know whether a journal is indexed in Thomson Reuters? Is my colleague correct? Is there an official list of journals indexed in Thomson and Reuters other than those in Clarivate Analytics? Thank you very much. Sincrely, Dr.Gabby