Hi Roman!
Thanks for getting in touch with us!
You can sell tickets and collect attendee information with Event Tickets and Event Tickets Plus. Once users purchase a ticket they will receive a ticket email which they can use to check-in at the event.
By default, each ticket has a security code generated, which you could use as an access credential. However, if you need another type of credentials added to the ticket email, like access to a webinar, you will have to customize our plugins to achieve that.
As a reference, let me share the following article about how you can customize our plugins > https://theeventscalendar.com/knowledgebase/themers-guide/
I hope that helps. Let me know if any follow up questions.
Best,
Victor