Creating new Tax codes

Hi,

Can any one tell me Tax codes are created by MM / FI Consultant?

I want to create 2 new tax codes: (FTXP)

one for the Service items &

Second one for the Excise items.

We are using TAXINN procedure. How can i create tax codes for these two in FTXP. What are the differences in b/n these 2 tax codes?