What should I include in my professional portfolio for a visa application as a freelance English teacher?

The user is applying for a visa from Vietnam and needs to submit a professional portfolio as a freelance English teacher for Italki HK Limited. They ask if providing screenshots of their profile page, showcasing their students, lessons, teaching style, and methods would suffice. Community comments suggest that these materials can be included in the portfolio and recommend adding proof of income, such as payment records from the platform for at least three to six months.