func formatsDates() {
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd"

    let ids: [Calendar.Identifier] = [.buddhist, .chinese, .coptic, .ethiopicAmeteAlem, .ethiopicAmeteMihret, .gregorian, .hebrew, .indian, .islamic, .islamicCivil, .islamicTabular, .islamicUmmAlQura, .iso8601, .japanese, .persian, .republicOfChina]

    ids.forEach {
        dateFormatter.calendar = Calendar(identifier: $0)
        print("For \($0) got: \(dateFormatter.string(from: Date()))")
    }
}


Output:

For buddhist got: 2567-03-01
For chinese got: 0041-01-21
For coptic got: 1740-06-22
For ethioaa got: 2024-03-01
For ethiopic got: 2016-06-22
For gregorian got: 2024-03-01
For hebrew got: 5784-06-21
For indian got: 1945-12-11
For islamic got: 1445-08-21
For islamic-civil got: 1445-08-20
For islamic-tbla got: 1445-08-21
For islamic-umalqura got: 1445-08-20
For iso8601 got: 2024-03-01
For japanese got: 0006-03-01
For persian got: 1402-12-11
For roc got: 0113-03-01