Can you be a little more specific on what you are trying to do? If you know what position in the record you want you could always us %Subst.
You put tabs into records the same way you put any character anywhere — use EVAL. Just like every other value, you specify what value you want along with where you want the value to go. How would you put the letter ‘A’ in the file? Do the same thing with a tab; it’s just another value.
All of that might be pointless though. Why put tabs into physical files when there are far better things to do with tabs? Put them into streamfiles where they’ll actually be useful.