A reverse-chronological resume lists your work experience starting with your most recent or current role and moves backward through time. It's the format recruiters expect, the format ATS parses most reliably, and it's appropriate for roughly 90% of job applications.
The structure is straightforward: contact info, a 2-4 sentence professional summary, work experience in reverse order, education, skills, and optional sections like certifications or projects. Each experience entry typically shows role title, company, location, dates, and 3-5 quantified achievement bullets.
Use a different format only when there's a specific reason: a combination format if you're changing careers and need transferable skills foregrounded, or an academic CV if you're in research. Otherwise, reverse-chronological is the safe, recruiter-trusted default.