Just been sent tracking code from Google Ads agency and need to add code to submit button. Need help
Info sent:

Add an onclick attribute directly to the code for the button or link that you'd like to track. The code that you use will depend on how the link or button is displayed on your site: as a text link, button or button image.
Add the code to a button: This code shows you how to add click tracking functionality to a button using the <button> tag. Replace 'https://example.com/your-link' with the URL for your website.
<button onclick="return gtag_report_conversion('https://example.com/your-link')">Submit</button>
Looked in Form > Settings > Customise HTML > Submit Button and code in place shows as below, and couldn't figure out how or where to add OnClick cod. Any help appreciated
<div class="frm_submit">
[if back_button]<button type="submit" name="frm_prev_page" formnovalidate="formnovalidate" class="frm_prev_page" [back_hook]>[back_label]</button>[/if back_button]
<button class="frm_button_submit" type="submit" [button_action]>[button_label]</button>
[if save_draft]<a href="#" tabindex="0" class="frm_save_draft" [draft_hook]>[draft_label]</a>[/if save_draft]
</div>