Sub GenerateData()
Dim count As Integer
Dim prefix As String
count = 10
prefix = "testuser"
Dim ws As Worksheet
Set ws = ThisWorkbook.Sheets("TestData")
' Clear existing data
ws.Range("A2:G1000").ClearContents
' Generate loop
For i = 1 To count
ws.Cells(i+1, 1) = i
ws.Cells(i+1, 2) = GenerateName()
ws.Cells(i+1, 3) = prefix & i & "@..."
Next i
End Sub