Search in a row and Find Column number matching from the data in a column:

In-order to search a row and find the column number which is matching the data in the column you can use the following formula: 

=MATCH(A7,'Sheet_Name'!A8:Z8,0)

lookup_value - A7 (Value in column A7 in the same sheet)

lookup_array - 'Sheet_Name'!A8:Z8 (Check row 8 in worksheet Sheet_Name)

match_type - 0

For detailed info regarding MATCH formula, please look MATCH.