If you wish to display a login form for users that have created an account during registration (or any other time), Easy Digital Downloads includes a short code for doing so.
This short code will display a simple login form. It should be placed on the page that you wish to act as the login page:
The short code also accepts an options redirect parameter that lets you set where users are redirected after they login. By default, users are sent back to the same page as the login form is displayed on, but if you want to send them elsewhere, such as your homepage, you can do this:
When someone is logged in the text "You are already logged in" appears instead of the form.