To select all the cells on a sheet using VBA you can use the .cells property of the worksheet, without specifying a specific cell.

An example of selecting all cells on Sheet1 using the code name Sheet1:

Sub MySelectAll()
     Sheet1.Activate
     Sheet1.Cells.Select
End Sub

An example of selecting all cells on Sheet1 using it’s tabname. You can replace “PlaceTabNameHere” with the name of your tab:

Sub MySelectAll2()
     Sheets("PlaceTabNameHere").Activate
     Sheets("PlaceTabNameHere").Cells.Select
End Sub