There are several ways to manage multiple workbooks and worksheets within a macro in Excel using VBA (Visual Basic for Applications). Here are some common approaches:

1. Looping Through Workbooks:

This method iterates through a collection of open workbooks or workbooks in a specific folder. You can then access worksheets within each workbook.

```vba
Sub ManageWorkbooks()

Dim wb As Workbook ' Declare a variable for each workbook
Dim ws As Worksheet ' Declare a variable for each worksheet

' Loop through all open workbooks
For Each wb In Workbooks
' Access worksheets within the current workbook (modify as needed)
For Each ws In wb.Worksheets
' Perform actions on the worksheet (e.g., copy data, format cells)
Next ws
Next wb

End Sub
```

2. Specifying Workbook and Worksheet Names:

This method allows you to directly reference specific workbooks and worksheets by name.

```vba
Sub ManageSpecificSheets()

Dim wbSource As Workbook ' Workbook containing source data
Dim wbDest As Workbook ' Workbook for destination data (optional)
Dim wsSource As Worksheet ' Worksheet with source data
Dim wsDest As Worksheet ' Worksheet for destination data (optional)

' Set workbook and worksheet objects
Set wbSource = Workbooks("MySourceData.xlsx") ' Replace with actual filename
Set wsSource = wbSource.Worksheets("Sheet1") ' Replace with sheet name

' Optional: Set destination workbook and worksheet (if copying data)
' Set wbDest = Workbooks("MyReport.xlsx")
' Set wsDest = wbDest.Worksheets("ReportData")

' Perform actions on the specified worksheets

End Sub
```

3. Using File System Objects:

This method utilizes the file system object library to open and manage workbooks located in a specific directory.

```vba
Sub ManageFolderWorkbooks()

Dim fso As Object ' File System Object
Dim folderPath As String ' Path to the directory containing workbooks
Dim wb As Workbook ' Declare a variable for each workbook

' Set folder path and create File System Object
folderPath = "C:\MyExcelData\" ' Replace with actual path
Set fso = CreateObject("Scripting.FileSystemObject")

' Loop through all Excel files in the folder
For Each file In fso.GetFolder(folderPath).Files
If Left(file.Name, Len(".xlsx")) = ".xlsx" Then ' Filter for Excel files
Set wb = Workbooks.Open(folderPath & file.Name)
' Access worksheets within the current workbook (modify as needed)
wb.Close SaveChanges:=False ' Close workbook without saving changes
End If
Next file

End Sub
```

Important Considerations:

* Remember to replace file paths and sheet names with your actual data.
* Error handling is crucial for robust macros. Implement error handling to gracefully manage situations where workbooks or worksheets might not exist.
* Be mindful of performance when working with large datasets. Consider optimizing your loops and using efficient methods for data manipulation.

These are just a few examples, and the specific approach depends on your needs. For more complex scenarios, you may need to combine these methods or explore additional VBA functionalities.