What a great question! At the Extension we do not recommend specific products or apps. I did find two articles about garden journaling (see below). They give an overall review of journaling. I personally have been documenting my vegetable/flower/fruit journey for 14 years. I use a blank journal to document planting, types, dates, weather, etc.. I use graph paper to hand draw my vegetable beds and document crop rotation. Lastly, I use a basic storage container to keep my seeds organized. I know some gardeners prefer to document online and keep ongoing files and journals, including drawings of crop rotation. There are different seed storage units that are sold online, either from a gardening company or through larger retailers. Do what works for you and, just like your yard, you can adjust along the way. 

https://extension.umn.edu/yard-and-garden-news/take-notes-now-healthier-garden-next-year

https://hennepinmastergardeners.org/the-garden-journal-a-tool-you-may-have-overlooked/