Your Website Running on WordPress and Using Hestia Theme is not showing the Calendar Icon for the Travel/Tour Booking Form?

It sounds like you’re using the Hestia WordPress theme, and its CSS is unintentionally styling an <iframe> form’s calendar icon (likely from a date picker inside the iframe).

Login to WordPress admin section and go to Appearance > Customize > Additional CSS

There add this following code:

#containername input[aria-label="Pickup date"] {
    border: 1px solid #b8c0cc !important;
    background-color: #fff !important;
    background-image: none !important;
    box-shadow: none !important;
    height: 48px !important;
    min-height: 48px !important;
}

Now, go to the page where you are embedding the form. There click on the + sign in the text area and add ”Custom HTML’ option. There, add the code you received from your partner for embedding. For an example:

<div id="containername" style="display: flex; justify-content: center; align-items: center; min-height: 100vh;">
<script type="text/props">
{        
"partner_id":"########",
"iframe": true
}

</script>
</div>
<script src=" https://link"></script>

Now, test the page. It should be fine.