How many Indians will be there at the opening ceremony march?

19 athletes and six officials will be a part of the Indian contingent for the opening ceremony.

Table Tennis: Sutirtha Mukherjee, Sathiyan Gnanasekaran; Sailing Vishnu Saravanan, K.C. Ganapathy, Varun Thakkar, Nethra Kumanan; Fencing: Bhavani Devi; Gymnastics: Pranati Nayak; Swimming: Sajan Prakash; Boxing: MC Mary Kom (Flag Bearer) Simranjit Kaur, Lovlina Borgohain, Pooja Rani, Amit Panghal, Manish Kaushik, Ashish Kumar, Satish Kumar; Hockey Manpreet Singh (Flag Bearer), Tennis: Ankita Raina

Officials: Shri Birender Prasad Baishya (Chef de Mission), Dr. Prem Verma (Deputy Chef de Mission), Dr. Arun Basil Mathew (Team Doctor), M.P. Singh (Table Tennis, Manager/Team Leader), Muhammad Ali Qamar, (Boxing, Coach), Lakhan Sharma, Coach (Gymnastics)

https://thebridge.in/tokyo-2020/indians-participating-tokyo-olympics-opening-ceremony-23264