booking form in responsive desig

at the moment you need custom css styling to make this work or modify template file at events-manager/templates/placeholders/bookingform.php

to use templates: https://wp-events-plugin.com/documentation/using-template-files/

eg. wp-content/themes/Your Theme/plugins/events-manager/placeholders/bookingform.php

Thank you, that’s clear so far. Unfortunately, I have not yet found the place where I can customize the presentation of the booking form and the login form so that they are no longer displayed in columns side by side. I would like to arrange login form after the booking form. How can I do that?

you can try something like this added in your theme style.css or admin > theme options > custom css

.em-booking-form-details {
    width: 620px !important;
}

.em-booking-form-details label {
    width: 190px !important;
}