Is it possible to find out the source of traffic from the application form?

Question

contextual advertising

Is it possible to find out the source of traffic from the application form on the site?
For example, there is a site on modx, the client came through some kind of advertising, left a request and the letter came out
Name: Vladimir
Phone: [phone]
Advertising: search results (Contextual advertising, etc.) The
question is more about how realistic it is?
If yes, then I ask for clarification or a link to the documentation, if not, then I will be grateful for an alternative option. (The main thing is to understand where the person who left the application came from?)

Answer 1

This is not a problem at all, you need UTM tags. I don't know what it looks like in modx, but a simple form with utm tags looks like this:

<form >
<input type="hidden" name="utm_source" value="<?php echo isset($_GET['utm_source']) ? $_GET['utm_source'] : '' ;?>" />
<input type="hidden" name="utm_medium" value="<?php echo isset($_GET['utm_medium']) ? $_GET['utm_medium'] : '' ;?>" />
<input type="hidden" name="utm_campaign" value="<?php echo isset($_GET['utm_campaign']) ? $_GET['utm_campaign'] : '' ;?>" />
<input type="hidden" name="utm_content" value="<?php echo isset($_GET['utm_content']) ? $_GET['utm_content'] : '' ;?>" />
<input type="hidden" name="utm_term" value="<?php echo isset($_GET['utm_term']) ? $_GET['utm_term'] : '' ;?>" />
<input type="text" name="name" placeholder="Ваше имя">
<input type="text" name="phone" placeholder="Телефон" required>
<button type="submit">Отправить</button>
</form>

Utm tags will work only in a file with the "PHP" extension, letters will come like this:
Username: Vasya
Phone: [phone]
utm_source: google
utm_medium: cpc
utm_campaign: utm
utm_content: ad2 utm_term
: utm tags
internet shaft :)