I have a website with an increasing traffic so I decided to make it as a business and add ads into the website. I'm currently in the process of registering my business and I don't get how would I record my Income. If it was a traditional business where you sell a product or offer a service, you can get a bill or something but in my case I don't have anything like that and I'm not 100% sure on how to present the spreadsheet file? Thanks.
You can invoice your advertisers and use the date of the invoice for tax purposes. Some advertisers may want to pay monthly, weekly etc so that would require multiple entries as income on the relevant dates.