I want to add one user manually to the database and that user will be responsible for adding other users to the database from the client side.
Is it possible to use Meteor accounts package and view only the login option, without registration?
Yes, you can turn off the register option. see the customization guide here: https://github.com/meteor-useraccounts/core/blob/master/Guide.md#disabling-client-side-accounts-creation
I would recommend using the alanning:roles package so that you can define an admin role