Pronouns are how a person needs to be addressed. It is important to not assume an individual's pronouns based on their appearance or their clothes. A respectful way of asking someone's pronouns is by starting a conversation stating your pronouns. This gives a healthy start to a conversation and shows that you care about the person expressions and about other gender identities.
https://lgbtq.wwu.edu/pronouns/
https://uwm.edu/lgbtrc/qa_faqs/why-is-it-important-to-respect-peoples-pronouns/