The answer is your income tax return. Tips are taxable income, so they have to be reported there, not just logged privately.
Working behind the chair as an independent contractor, you're responsible for tracking every dollar you take home in tips alongside your service income, and reporting all of it when you file. A daily appointment log or a business plan might help you stay organized day to day, but neither one satisfies the actual reporting requirement.
This is 1 of the real Business questions in fadejunkie's 299-question bank. See the Business practice questions page for a fuller sample, or try the Business practice quiz and flashcards for free. A one-time $15 lifetime pass unlocks the complete question bank across all 13 tested topics.
More real Business questions: Which State Bans Booth Rental Outright?, Who Actually Writes the Laws Barbers Follow?, What Ownership Structure Has Stockholders?, What's a Base Salary Plus Commission Pay Setup Called?, and 11 more on the Business practice questions page.
Browse every topic on the Practice Question Hub, or see the Texas Barber State Board Exam Guide for the full exam process — required hours, PSI scheduling, and fees.