Change of the button value

Hello.
You can configure it at the Booking > Settings > Form page.
Kind Regards.

Thank you, where exactly?

I see only my fields.

Among “Add New Field” there is no button to be used.

Hello.
It’s at the bottom of the page, at the latest version update.
Kind Regards.

I have the premium version 8.7.10 (small single site). Does that mean that this functionality was not there?

Hello.
In the premium version of Booking Calendar possible to change the title of send button, as well.
1) If you are using the “Simple Booking Form” configuration (activated the option “Simple Booking Form” at the Booking > Settings General page in form section), then it’s possible to change the title of send button in update 8.8.1 or newer.
You can request the new update of Booking Calendar on this page: https://wpbookingcalendar.com/request-update/

2) Otherwise you need to deactivate the using “Simple Booking Form” configuration, and then configure the send button via shortcodes at the Booking > Settings > Form page.
For example:
<p>[submit class:btn "Submit Booking"]</p>
Please use shortcode generator at the right side of the Booking > Settings > Form page for the fast and correct creation of booking form fields.
Watch it in this video guide https://wpbookingcalendar.com/help/booking-form-fields-settings-video-tutorial/

P.S. Please note, this forum is only about the support of Booking Calendar Free version. If you will have any questions about the paid version, then contact here https://wpbookingcalendar.com/contact/