Will GSTN provide separate user ID and password for Tax Professional to enable them to work on behalf of their customers (Taxpayers) without requiring user ID and password of taxpayers, as happens today?

Yes, GSTN will be providing separate user ID and
Password to Tax Professional to enable them to work on
behalf of their clients without asking for their user ID and
passwords. The tax professional will be able to do all the
work on behalf of taxpayers as allowed under GST Law
except final submission, which will be done by the taxpayers
using e-sign (OTP) or Digital Signature Certificate.