Hi there,
Thank you for reaching out to us!
I believe that what you are asking for is related to Community Events submission form and not Events Calendar PRO, is that correct? Please let me know if I misunderstood your request. Unfortunately we don’t have out-of-the-box a shortcode for community events submission form. I would recommend proposing this feature in our User Voice page to let us know. Other users can then up-vote it, giving us a great idea of how much demand there might be (or, if you can find a suitable existing request, you can in turn up-vote that).
Regarding your second question about customization: You can use template overrides to edit the Community Events submission form. You can copy the default templates from the-events-calendar-community-events/src/views/community/modules, paste them in [your-theme]/tribe-events/community/modules/title.php and modify as necessary. You will find mor info about this in our Themer’s Guide.
I hope this helps! If you have any other questions at all please feel free to let me know and I’d be happy to help as best I can!
Cheers,
Patricia