Can I include a discount code in the registration URL?

Yes you can!

You can modify your registration page URL to contain a discount code. This will automatically fill the discount code in the box. Here's an example URL:

http://example.com/register/?discount=CODEHERE

The main URL should be the page containing your registration form shortcode.

Then add ?discount=CODEHERE on the end, where CODEHERE is your discount code.

For the below discount code, my URL might be: http://example.com/register/?discount=half_off