I assume you are referring to a Microsoft Teams Webinar? Just checking as this is the Learning conversation. But if you are then when you create the webinar you are the Organiser and have the same rights as presenter role, plus ability to see sign up, edit the meeting etc (see
https://support.microsoft.com/en-us/office/roles-in-a-teams-meeting-c16fa7d0-1666-4dde-8686-0a0bfe16... as webinars are basically Teams meetings with sign up options).
You can add your name and bio in the webinar sign up page which your potential attendees see, if that is why you want to add yourself as a presenter. This is separate to the 'Presenter' option when you set up the meeting.
