You might use this online form to keep track of anything you like. A template below, for example, is focused on meal tracking. Imagine you want to remember what exactly you ate and drank throughout the week? Well, this is a perfect system to use.
Filling out digital forms is both faster and more secure than using paper. All of your responses are stored safely in your cloud account, and only you can access them. Digital tracking also makes it much easier to analyze and visualize data. You might, for example, export your submissions in CSV format and later use Google Sheets (or a data visualization tool of your choice) to create beautiful charts.
While a template below is definitely a good place to get started, you can easily tailor this form to your purposes. Just click the button "Use this template" to make it yours.