1. Assume all your workbooks in which you want to change the footer are in a folder named Data saved on your desktop. This folder should only have those Excel files and nothing else
2. Open a blank workbook and enter the following code in a module
Z = 1
F = Dir("C:\Users\Ashish\Desktop\Data\*.XL*")
Do While Len(F) > 0
Range("A" & Z).Formula = F
F = Dir()
Z = Z + 1
When this code is run, it will list down all XL* files in the Data folder from cell A1 onwards (of the blank workbook which you just opened in step 2).
3. In the same open workbook, enter the following code in another module
Application.ScreenUpdating = False
Dim ws As Worksheet
For n = 1 To Range("A1").currentregion.rows.count
Workbooks.Open Filename:="C:\Users\Ashish\Desktop\Data\" & Range("A" & n)
For Each ws In ActiveWorkbook.Worksheets
.CenterFooter = "&""Calibri,Regular""&10Company Name"
Set ws = Nothing
ActiveWindow.View = xlNormalView
Application.StatusBar = False
Application.ScreenUpdating = true
When you run this code, it will apply your desired footer to all worksheets of all workbooks in the Data folder
Hope this helps.
Do let me know how this works for you.