Section("Enter value:)"){
         TextField("Input value", value: $value1, format: .number)
       }
       .textFieldStyle(.roundedBorder)
       .keyboardType(.decimalPad)

Given this fragment of code, whenever the TextField content is changed, I want to execute a function. I looked at " .onEditingChanged", but it seems to have been deprecated. Is there a way to do this?

I would say all depends on what you need to achieve. Below first textfiled is executing function as soon as you change the value1, the second texfield is executing function as soon as you switching focus to that textfield.

struct ContentView: View {
    @State private var value1 = 0
    @State private var value2 = 0
    @FocusState private var isEditing

    var body: some View {
        Section {
            TextField("Enter value", value: $value1, format: .number)
                .textFieldStyle(.roundedBorder)
                .keyboardType(.decimalPad)
                .onChange(of: value1) { oldValue, newValue in
                    print(oldValue)
                    print(newValue)
                }

            TextField("Enter value", value: $value2, format: .number)
                .foregroundStyle(isEditing ? .green : .red)
                .focused($isEditing).keyboardType(.decimalPad)
                .textFieldStyle(.roundedBorder)
                .keyboardType(.decimalPad)
        }
        .padding()
    }
}

Thank you!