If you want to provide a video for free and want users to sign up to access it, we recommend changing your pricing from Free For All Users to Gated. This will help you know who is watching your content and obtain their contact information.
Navigate to Content > Video. Click on the video you want to make free.
Under Access enable Gated.
Leave the Subscription plan as Choose plan, leave all the pricing options unchecked, then click Save. Add the free video to a freebie bundle.