It clear to me what you want to do but unclear why.
1) A footer is always placed at the bottom of a document, which means a fixed position.
2) If the 3 cells to the right are empty, then the text in the first cell will be visible.
Anyway, the following code will go through column A looking for the 3 phrases and merging the next 3 cells to the right of the phrase found:
Dim lRow As Integer
lRow = Range("A" & Rows.Count).End(xlUp).Row
For Each cell In Range("A1:A" & lRow)
If cell = "Other grades include" _
Or cell = "Data reflect grades posted as of" _
Or cell = "Report produced by" Then
Range(Cells(cell.Row, "A"), Cells(cell.Row, "D")).Merge