In the event dashboard, click on "Registrations"

From the sidebar, select “Setup Tickets”

This will take you to a page with the list of all tickets. Click on "Edit" to open the ticket you want to disable.

Open the advanced section, and uncheck the “Is Visible?” checkbox.

Click save to persist your changes. Once saved, this ticket will no longer be available for selection in the registration form.

How to disable a ticket so that it does not show up in the registration form?