Personal Information
As you know from the App Store description, the Simple Journals.app lets you keep a personal journal, where entries are organized chronologically, and (in the future) can be tagged.
iCloud
If you don't use iCloud, none of your profile data is ever sent from your device.
If you use iCloud, your journal entries are automatically synchronized between all of your devices. As the developer, and by nature of the CloudKit technology behind iCloud, I won't have access to any of your data.
If you opted-in to crash logs and session usage in iOS, that data is reported to me by Apple, anonymized, via AppStoreConnect.
Permissions
These are no permissions requested by Simple Journals.app at this time.