Run code (Len-Instr-Mid) in all nonempty cells

Hello.
In Excel 2016 I have a Sheet with a range of cells with data and others cells with no data.
I have a code which works well in a cell with data.
However, I need to write the code into a loop to apply the code in all cells with data.
I've searched the web trying to find help on how to complete my script, but I just can't seem to get how to do it.
Any help is welcome

Sub lenInstrMid()
Dim Z As String
Dim X, y as Integer

Z= Sheets(1).Cells(1,11)
x= Len(Z)
Y= Instr(Z, "_")
Z= Mid(Z,1, y-1)
Sheets(1).Cells(2,11) = Z

End Sub

Hello gipsyfkls14,

Does your data start in cell "A11" and continue down column "A" ?

Hello gipsyfkls14,

One more thing, what do you consider to be an empty cell? I know sometimes people consider a zero value as empty.

Hello gipsyfkls14,

This should work for you ...

Note: You may need to change the worksheet name from "Sheet1" to whichever sheet the data is on.

Sub Macro1()

    Dim Cell    As Range
    Dim Rng     As Range
    Dim RngEnd  As Range
    Dim Wks     As Worksheet
    
        Set Wks = Worksheets("Sheet1")
        
        Set Rng = Wks.Range("G2")
        Set RngEnd = Wks.Cells(Rows.Count, "G").End(xlUp)
        
        If RngEnd.Row < Rng.Row Then Exit Sub
        
        Set Rng = Wks.Range(Rng, RngEnd)
        
            For Each Cell In Rng.SpecialCells(xlCellTypeConstants)
                Cell.Offset(0, 1).Value = Left(Cell, InStr(1, Cell, "_") - 1)
            Next Cell
        
End Sub

Hello Hello gipsyfkls14,

The attached workbook has the macro below added to it.

Sub Macro1()

    Dim Cell    As Range
    Dim LastCol As Long
    Dim LastRow As Long
    Dim Rng     As Range
    Dim Wks     As Worksheet
    
        Set Wks = Worksheets("Sheet1")
        
        LastRow = Wks.Cells(Rows.Count, "A").End(xlUp).Row
        LastCol = Wks.Cells(1, Columns.Count).End(xlToLeft).Column
        
        Set Rng = Wks.Range("G2").Resize(LastRow - 1, LastCol - 6)
        
        On Error Resume Next
        
            For Each Cell In Rng.SpecialCells(xlCellTypeConstants)
                Cell.Value = Left(Cell, InStr(1, Cell, "_") - 1)
            Next Cell
        
        On Error GoTo 0
        
End Sub

Hello gipsyfkls14,

De nada.