Site of promotion
https://www.bitdefender.com/media/html/consumer/new/get-your-90-day-trial-opt/index.html
Event
Extended Trial
Instructions
follow the link above and enter your email to receive a download link to bitdefender total security 2019

pica

Level 1
you can use it after the 3 months for free. use the switch account button and make another one with any temporary mail. i never paid for bitdefender. i just do that.
If your account is not yet expired, it can be extended; request the trial but dont click it until a few days before the existing account expired,then you can extend existing account for another 90 days.