Do you want many influencers to respond to the campaign, with detailed posts and effective results? Then, just a link on the website isn't enough — provide them with the most detailed information.
Specify all the critical data: what is the main idea of the event, what is the program, who are the most expected guests, where will the action take place, why should one be interested, etc. And, what's also important, why a particular influencer should be interested in this event.
In this way, you will not only attract influencers for collaboration, but they'll also most likely visit the event and invite even more people than expected.