For your reference - you might want to see IRS
publication 463 page 25https://www.irs.gov/pub/irs-pdf/p463.pdfWhat Are Adequate Records?You should keep the proof you need in an account book, diary, log, statement of expense, trip sheets, or similar record. You should also keep documentary evidence that, together with your record, will support each element of an expense.Documentary evidence. You generally must have documentary evidence, such as receipts, canceled checks, or bills, to support your expenses.Adequate evidence. Documentary evidence ordinarily will be considered adequate if it shows the amount, date, place, and essential character of the expense.For example, a hotel receipt is enough to support expenses for business travel if it has all of the following information.The name and location of the hotel.The dates you stayed there.Separate amounts for charges such as lodging, meals, and telephone calls.A restaurant receipt is enough to prove an expense for a business meal if it has all of the following information.The name and location of the restaurant.The number of people served.The date and amount of the expense.If a charge is made for items other than food and beverages, the receipt must show that this is the case.Canceled check. A canceled check, together with a bill from the payee, ordinarily establishes the cost. However, a canceled check by itself does not prove a business expense
without other evidence to show that it was for a business purpose..I appreciate if you take a moment to rate the answer.Experts are ONLY credited when answers are rated positively.If you still have any doubts, need clarification - please be sure to ask.I am here to help you with all tax related issues.