I am using multiple companies in single login and now I want to separate my both companies and different login, so kindly help me with this

You'll need to have separate login credentials, mahesh_s.

Choose which company you'll want to have a separate log in. Then, add a new user in that company and enter a different email address since it will serve as the user ID. Accept the invite and create another password. Once done, transfer the Master Admin role to the newly added user. 

For more details in handling your account, you can use these references: 

• Create or add another company file to QuickBooks Online
• Change your email, user ID, or password for QuickBooks Online

Let me know if you have other questions. Take care!