mxNotes 4+

mxNotes is a free app for Mac, iPhone and iPad to manage notes, tasks (i.e., to-dos) and documents in a unified way. Each note, consisting of a title and a text, can have a deadline, which may be recurring (every day, week, etc.), an indication of its possible completion and a possible file of any kind attached to it. This feature allows to archive various documents and files with this app and to find them very easily.
The notes can be tagged with predefined or custom tags, sorted and filtered very easily. They may also be synchronized with the Apple calendar, if the user allows this, or imported from and exported to Apple Reminders.
Notes are automatically synchronized on iCloud between the various devices associated with the same Apple account. However, it is possible to export the notes in text format or as a CSV file. The latter can be opened with Numbers or another spreadsheet, or imported into other apps.
The app doesn't require any permission to access user's data, except the calendar and the remainders if he or she allows this.

For more information on all the features of the app, open the on line manual with a click on the link below "App support".