I like “Fasting - Intermittent Fasting” by Leap Fitness Group. The built-in notes are very helpful, the interface is easy to use and it records everything I can imagine you would need.
I’ve used this app since November last year.
Edit:
The low ratings for this app are related to the ads in the free version. I posted for no-ads and cloud storage (I think - I can sync my data)
Otherwise, it has a 4.9 overall rating.
The internal notes have really helped me with being hungry while fasting and with emotional eating. I would also snack when I was bored.