Company B must first provide company A with the bank account information of company B's legal person account: company name, account number, bank account number and bank account number. Then Company A can endorse the electronic bank acceptance bill to Company B in the online banking system.
After the operation of Company A is completed, Company B finds the corresponding signing options in the online banking system (the online banking of each bank is different and similar), and Company B clicks on this electronic bank acceptance bill and chooses to sign the bill.