Is there a way to import data from .csv to active excel sheet?

Add this code to create a QueryTable in the PO Data sheet to your data source

Once you have created the QueryTable you can then just right click Refresh the data (or refresh on open)

Sub CSV_Import()
Dim ws As Worksheet, strFile As String

Set ws = ActiveWorkbook.Sheets("PO Data") 'set to current worksheet name

strFile = Application.GetOpenFilename("Text Files (*.csv),*.csv", , "Please select text file...")

With ws.QueryTables.Add(Connection:="TEXT;" & strFile, Destination:=ws.Range("A1"))
     .TextFileParseType = xlDelimited
     .TextFileCommaDelimiter = True
     .Refresh
End With
End Sub

There are lots of ways to get data into Excel. Querytables (as demonstrated by The_Barman), SQL, Import Wizard etc.

Usually the method depends on how clean the data is presented on the files you need to import and if you know exactly how it's laid out. Eg if there are empty rows, mixed data types, merged cells etc then it can be a nightmare.

Below is a slower 'brute-force' method which will usually get all data by opening the file in Excel first. It's often the last thing to do when other methods fail.

Option Explicit

Public Sub ImportData()
Dim CSVFilename As String
Dim writeToFilename As String
Dim writeToSheet As String
Dim readXL As Workbook
Dim readWS As Worksheet
Dim writeXL As Workbook
Dim writeWS As Worksheet
Dim UsedRng As Range



    CSVFilename = Environ$("USERPROFILE") & "\Desktop" & "\SO2PO.csv"
    writeToFilename = Environ$("USERPROFILE") & "\Desktop" & "\Open Order.xlsx"
    writeToSheet = "PO Data"


    Set writeXL = GetObject(writeToFilename)
    Set writeWS = writeXL.Sheets(writeToSheet)
    'writeWS.Parent.Windows(1).Visible = True


    Set readXL = GetObject(CSVFilename)

    With readXL

        Set readWS = readXL.Sheets(1)
        Set UsedRng = RealUsedRange(readWS)
        writeWS.Range(UsedRng.Address).Value = UsedRng.Value

    End With

    'close CSV without saving
    readXL.Close SaveChanges:=False
    Set readWS = Nothing
    Set readXL = Nothing

    'close template with save
    writeXL.Close SaveChanges:=True
    Set writeWS = Nothing
    Set writeXL = Nothing


End Sub


Public Function RealUsedRange(ByVal WS As Worksheet) As Range
'Find used range
    Dim FirstRow        As Long
    Dim LastRow         As Long
    Dim FirstColumn     As Integer
    Dim LastColumn      As Integer

    On Error Resume Next

    With WS

        FirstRow = .Cells.Find(What:="*", After:=.Cells(.Rows.Count, .Columns.Count), LookIn:=xlValues, LookAt:= _
        xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext).Row

        FirstColumn = .Cells.Find(What:="*", After:=.Cells(.Rows.Count, .Columns.Count), LookIn:=xlValues, LookAt:= _
        xlPart, SearchOrder:=xlByColumns, SearchDirection:=xlNext).Column

        LastRow = .Cells.Find(What:="*", After:=.Range("A1"), LookIn:=xlValues, LookAt:= _
        xlPart, SearchOrder:=xlByRows, SearchDirection:=xlPrevious).Row

        LastColumn = .Cells.Find(What:="*", After:=.Range("A1"), LookIn:=xlValues, LookAt:= _
        xlPart, SearchOrder:=xlByColumns, SearchDirection:=xlPrevious).Column

        Set RealUsedRange = .Range(.Cells(FirstRow, FirstColumn), .Cells(LastRow, LastColumn))

    End With

    On Error GoTo 0

End Function

If you're going to use querytables make sure you clean up after, leftover query tables caused me a few headaches in a downstream process.

' get the file to the data sheet
Set ws = ActiveWorkbook.Sheets("Data")
With ws.QueryTables.Add(Connection:="TEXT;" & "mydata.csv", Destination:=ws.Range("A1"))
    .TextFileParseType = xlDelimited
    .TextFileCommaDelimiter = True
    .Refresh
End With

' delete the querytable if there is one
On Error GoTo nothingtodelete
    Sheets("Data").QueryTables(1).SaveData = False
    Sheets("Data").QueryTables.Item(1).Delete 
nothingtodelete: