Is there a separate place to keep management records?

The thing I'm working on the hardest these days is weight management.

When managing your weight, it is very important to keep a record of your weight.

Looking back, you can reflect, gain more will, and see the progress.

I used to roughly write it down in a memo app, but now I'm thinking of writing it down properly separately!

Does anyone know of a good app or method for keeping such management records?