I assume you want to know what gift to take for the engagement. The best buy would be to invest in a good book about how to know your partner or tips to have a better positive attitude in life. Another good book would be a wedding planner with references of planners of your city.
Traditionally, gifts are not required, but in reality, most people still bring them. It doesn't have to be expensive, just something that shows how happy you are for them.
The best thing is to find out what it is they both need or want. You can give them cash. Or you can get them something they can use on their honeymoon.
If you are going on a engagement party then take a flower bouquet with you & also if possible a gift which is a writsh watch for both the guy and the girl. And also remember to wish them with great wishes to them. If not wrist watch then Saree which will impress the girl.
Usually personal items such as nighty's to candles if it is just for the girl. If for both then check out their store registration list and buy inexpensive items.
I would say its not nessecery to bring a gift, becasue you will getting them a gift for the wedding. I think a card that say congratulations is gift enough.
If the couple has created a gift registry then an item from the registry would be a sufficient gift providing that there are gifts on the registry within your price range. If not, then a cash gift in an amount that you are comfortable with would be an advisable gift.