Send them invites for your webinars or whitepapers. Send an email regarding it, and wait for their response on it.
If there is no need for a live event, you can use on-demand presentations for various big webinar concerns. One of the advantages is that it provides ease of content creation for subject matter experts, becaues they can record their portion online video at their convenience.
webinar don't always attend the webinar. Adopt measures to convert these registrants to attendees.
? Choose a relevant topic: