Allow data Entry into Excel Worksheet Via User Form Only

How to Allow data Entry into an Excel Worksheet Via User-Form or Macro Only.
Here's the complete VBA code:
Option Explicit

Private Sub cmdExit_Click()
Unload Me
End Sub

Private Sub cmdTransfer_Click()
Dim erow As Long
erow = Sheet1.Cells(Rows.Count, 1).End(xlUp).Offset(1, 0).Row
Cells(erow, 1) = txtCustomerName
Cells(erow, 2) = txtMobile
End Sub

Private Sub Workbook_Open()
ActiveWorkbook.Sheets("Sheet1").Protect Password:="macr0@entrY", userinterfaceonly:=True
UserForm1.Show
End Sub

Private Sub cmdDisplayUserForm_Click()
UserForm1.Show
End Sub
Further Reading: https://www.exceltrainingvideos.com/allow-data-entry-into-excel-worksheet-via-user-form-only/