If you have to present a talk or other presentation, find the person who will introduce you and give them a card with your name and the subject PRINTED OUT to make it easy for them.
If there is a full, formal program, then it’s worthwhile to have a brief, clear introduction printed out for them. If they don’t use it, you’re no worse off! But, most Masters of Ceremonies will appreciate the effort you’ve taken to ease the load on them slightly and they’ll sometimes give you an unexpected boost with their remarks.