Question

What is the most efficient way to make the text in a row bold in every worksheet in the file in excel?

Answer 1

Write a macro to cycle through all the worksheets and make the row bold. Something like this:
maxSheets = Sheets.Count
For x = 1 To maxSheets
Sheets(x).Activate
Rows("1:1").Select
Selection.Font.Bold = True
Cells(1, 1).Select
Next

Answer 2

This will also work:
maxSheets = Sheets.Count
For x = 1 To maxSheets
Sheets(x).Rows("1:1").Font.Bold = True
Next