Salesforce login URL to login to system directly on single click

If the instance is Sandbox:

https://test.salesforce.com/login.jsp?pw=instancepassword&un=instanceUsername

For example if instance username is test@gmail.com and password is India123 ,then URL to login will be

https://test.salesforce.com/login.jsp?pw=India123&un=test@gmail.com

If the instance is production:
https://login.salesforce.com/login.jsp?pw=instancepassword&un=instanceUsername

For example if instance username is test@gmail.com and password is India123 ,then URL to login will be

https://login.salesforce.com/login.jsp?pw=India123&un=test@gmail.com