Hello.
Its possible to have such type of form customization in the paid versions of Booking Calendar.
In paid versions of Booking Calendar please open the Booking > Settings > Fields page in admin panel, then in the action toolbar, select “2 Columns form template” and click on “Reset” (or “Both”) button, to reset the exist booking form customization to this default.
You will have booking form customization, like this:
<div style="float:left;margin-right:10px; " > [calendar] </div>
<div style="float:left;" >
<p>First Name (required):<br />[text* name] </p>
<p>Last Name (required):<br />[text* secondname] </p>
<p>Email (required):<br />[email* email] </p>
<p>Phone:<br />[text phone] </p>
<p>Adults: [select visitors class:span1 "1" "2" "3" "4"] Children: [select children class:span1 "0" "1" "2" "3"]</p>
</div>
<div style="clear:both">
<p>Details:<br /> [textarea details 100x5 class:span6]</p>
[captcha]
<p>[checkbox* term_and_condition use_label_element "I Accept term and conditions"]</p>
<hr/><p>[submit class:btn "Send"] </p>
</div>
Click on “Save changes” button and then test it.
You can test Booking Calendar live demos at this page https://wpbookingcalendar.com/demo/ to be sure in functionality and do not have misunderstanding.
Kind Regards.