Head to Event Settings > Core Settings and scroll to Event Logo:

Select 'Choose File' and upload your logo and hit Save.

Once uploaded, this logo will appear in certain places:

Shown at the top of all your forms, above the Form name and Event name.

If you don't have custom ticket artwork set up, it will appear on your passes.

If you have custom ticket artwork, then that will display instead.

When editing your email templates, you can cleverly add the logo in to each email template using the {LOGO_URL} placeholder.

Simply add it into the template like you would with any other placeholder.

In the received email it will then automatically generate the logo in the email, like this:

For any invoices, receipts or purchase orders, the logo will also appear at the top of the document.