For any exam, there are some basic things you need to carry
1. Hall Ticket
2. Identity proof (Aadhar, voter, driving licence, college id, pan card etc)
3. Pen/ pencil
You also need to keep in mind that for online exam, you are not supposed to carry certain things
1. Electronic gadgets
2. Books, guides, rough sheets
3. Hardware /software items
4. Sometimes they will not allow metal items on the body (like gold, copper etc and even belt)

Hello,
For which entrance exam you are asking about so that we can guide you properly.
For most of the online entrance exams you need to carry the following things to the examination centre-

• ADMIT CARD
• ID PROOF
• STATIONERY ITEMS

Rough sheets will be provided to you at the examination centre.
Good luck.