I found a similar solution to this question in c# How to Select all the cells in a worksheet in Excel.Range object of c#?
What is the process to do this in VBA?
you have a few options here:
I personally use the Used Range and find last row and column method most of the time.
Here's how you would do it using the UsedRange property:
Sheets("Sheet_Name").UsedRange.Select
This statement will select all used ranges in the worksheet, note that sometimes this doesn't work very well when you delete columns and rows.
The alternative is to find the very last cell used in the worksheet
Dim rngTemp As Range
Set rngTemp = Cells.Find("*", SearchOrder:=xlByRows, SearchDirection:=xlPrevious)
If Not rngTemp Is Nothing Then
Range(Cells(1, 1), rngTemp).Select
End If
What this code is doing: