How can I export from Excel file to a csv file, where the file has leading zeros, in text format?

Export

If you need leading zeros, then Format should help.

You should also avoid selecting or activating anything.
Therefore I used a variable "i" for a loop over all rows.

As filenumber 1 may already be in use, it is better to use FreeFile.

Sub GravarArquivoCSV()
    Dim fileNum As Long
    Dim i As Long

    fileNum = FreeFile
    Open Range("E1").Value For Output As fileNum

    With Sheets("APR_CSV")
        i = 1
        Do While .Cells(i, "A").Text <> ""
            Print #FileNum, .Cells(i, "A").Value & ";" & _
                      Format(.Cells(i, "B").Value, "0000000000") & ";" & _
                      .Cells(i, "C").Value & ";" & _
                      .Cells(i, "D").Value
            i = i + 1
        Loop
    End With
    Close fileNum

    MsgBox "Arquivo gerado com sucesso!", vbInformation, "OK"
    Sheets("Autoline Controlo Compras").Activate
End Sub

Import

When you import this CSV into Excel, Excel recognises the numbers as numbers.
Therefore you have two options:

• keep it as number and give it a customized number format,
  e. g. "0000000000" shows numbers with leading zeros
• import it as text string by following VBA code

Please adapt the filepath and filename to your needs.

Public Sub ImportCSV()
    Dim wb As Workbook
    Set wb = Application.Workbooks.Add

    With wb.Worksheets(1).QueryTables.Add( _
        Connection:="TEXT;" & Application.DefaultFilePath & "\APR_CSV.csv", _
        Destination:=wb.Worksheets(1).Range("A1"))
        .Name = "APR_CSV"
        .FieldNames = False
        .RowNumbers = False
        .FillAdjacentFormulas = False
        .PreserveFormatting = True
        .RefreshOnFileOpen = False
        .RefreshStyle = XlCellInsertionMode.xlInsertDeleteCells
        .SavePassword = False
        .SaveData = True
        .AdjustColumnWidth = True
        .RefreshPeriod = 0
        .TextFilePromptOnRefresh = False
        .TextFilePlatform = XlPlatform.xlWindows
        .TextFileStartRow = 1
        .TextFileParseType = XlTextParsingType.xlDelimited
        .TextFileTextQualifier = XlTextQualifier.xlTextQualifierNone
        .TextFileConsecutiveDelimiter = False
        .TextFileTabDelimiter = False
        .TextFileSemicolonDelimiter = True
        .TextFileCommaDelimiter = False
        .TextFileSpaceDelimiter = False
        .TextFileColumnDataTypes = Array( _
            XlColumnDataType.xlGeneralFormat, _
            XlColumnDataType.xlTextFormat, _
            XlColumnDataType.xlGeneralFormat, _
            XlColumnDataType.xlTextFormat)
        .TextFileDecimalSeparator = "."
        .TextFileThousandsSeparator = ","
        .TextFileTrailingMinusNumbers = True
        .Refresh BackgroundQuery:=False
        .Delete
    End With
End Sub

Path of the Excel file

Please either use the ActiveWorkbook, which is the currently active file, or ThisWorkbook, which is the file with your VBA code. They are the same, if the file containing your VBA code also is the active file.

Use its Path, add a backslash "\" and add the desired CSV filename (e. g. "APR CSV Renault.CSV").

Experiment with his:

Private Sub DebugMyPaths
' always the file with THIS VBA code:
Debug.Print ThisWorkbook.Path & "\" & ThisWorkbook.Name
Debug.Print ThisWorkbook.FullName

' always the active Excel file:
Debug.Print ActiveWorkbook.Path & "\" & ActiveWorkbook.Name
Debug.Print ActiveWorkbook.FullName
End Sub