This inquiry will be the "guided" type, for two reasons. One is to provide a focus so that the instructions and examples below don't get too unwieldy. The other is to give you an example of what guided inquiry might look like. If an instructor has a particular curriculum goal, substantial progress can be made towards that goal by asking the student to ask a certain type of question. In this case, you will start your inquiry by choosing a composer whose work interests you. (You can choose a song writer, or a performer of largely-improvised works, but not a musician who primarily performs works composed by someone else.) One of the main ideas in music history/appreciation/theory curricula is that musicians influence and are influenced by the music of others. You will be asking about the influences on this composer's work or on the influence this composer had on the work of others. Although the specifics of what you learn will depend on your interests and prior knowledge, this is a "big picture" concept that you can learn more about whether you are a novice or a knowledgeable musician.
Asking questions that will have complex answers, such as "how" or "why," or sometimes "what," will help to produce well-rounded, in-depth inquiries. If you already have some idea of the kinds of influences on or by your chosen composer, you may be able to start with an inquiry-type question, such as "Why did Beethoven have such a substantial influence on Romantic-era composers?" or "What influence has Ravi Shankar had on American music?" or "How did church music influence Elvis Presley?"
Questions that involve "who," "where," or "when" usually lead to bits of knowledge rather than deeper understanding. However, if you do not know who influenced or was influenced by your composer-of-interest, you may have to start with that question. It is not unusual for inquiries to start with some early investigations that help to shape the direction of the inquiry. In fact, in this inquiry, rather than posing one question, you will pose and keep track of a whole series of questions that arise as you investigate, and this will help you identify the "good" inquiry question or questions that you create along the way.