@Brandon Baker spreadsheets can definitely be helpful. My issue with them though is you also need to keep a photo of the receipt. Some people scan them separately or just keep them in a bag in case they need them in the future. The other issue I had was I really dislike google spreadsheets on the phone. And excel for me is best used on my laptop, which means I have to wait and gather all the receipts to do it at the end of the day versus just logging things right there and then as they come in.
I now use an app called Tellus. It’s fast to log expenses and I can snap a photo and also classify it into a tax deductible category. It also generates p&l reports whenever I want. There are other products out there that also help with expense tracking. Also I add my mom and husband as co-managers so they can log things in too which they have when they handle things when I’m out of town. The app is free so worth checking out!