You with other account holders should visit the nearest branch to open a joint bank account with BMO.
If your banking account holders are family members, you can join them to your opened account in online banking.
However, the member can be required to visit the nearest branch to verify the identity and place of living (take passport, utility bill, bank statement, etc.).
Bank of Montreal can charge additional commissions for adding members to your account.
If you have additional questions, you should call 1-844-837-9228.