If you have watched only through Roku then you will need to create an account the next time you want to watch a movie on the Passionflix channel. 
Just find the movie you are interested in and follow the instructions on the screen.

After the account creation, you will be prompted to restore your subscription.

Please follow through with this step to connect your active Passionflix Roku subscription with your new Passionflix account. 

Afterwards, you can use the same credentials and watch on watch.passionflix.com, the iOS, and Android apps or on your Samsung and LG Smart TV.