A Preply.com bio is a tutor's profile, comprising a written description and a video introduction, designed to attract students by showcasing their teaching experience, skills, personality, and motivation to help students achieve their language learning goals. The written bio includes a catchy headline and structured sections for self-introduction, detailing teaching experience, and a call-to-action to encourage lesson bookings. The video serves as a brief, 15-20 second introduction, focusing on skills and ending with an encouragement to book.