According to the Indonesian immigration regulations, participants attending the activities on Exhibition are required to obtain a specific visa type known as the B221A visa.
For B211A ,please visit below link :
https://www.imigrasi.go.id/en/visa-kunjungan-satu-kali-perjalanan-b211a/
Most visitors to Indonesia need a visa to enter the country. As a visitors with visit activities, you can apply Visa Type : VOA
For VOA, please visit below link :
https://www.imigrasi.go.id/en/e-voa/