It is important to use in-text citations to identify where you are referring to another's work or idea. You should use an in-text citation either when you are using a quote, or when you are paraphrasing.
Quote: Information copied word-for-word from another author's work (Requires a page number as well as author and year).
Paraphrasing: Expressing another author's ideas in your own words.
The purpose of an in-text citation is to lead the reader to the correct entry in your reference list. Your in-text citation should contain enough information to achieve this.
Regardless of the type of information you are citing (be it a book, journal article, webpage, YouTube video etc.), your in-text citation will comprise of the author (or title) and date information relevant to that particular entry. As noted above, this leads readers to the correct entry in your Reference List.
Decide how to format your in-text citation based on whether you have an author name (and how many names you have), or a title for that entry.