How to change Joomla 3.9.15 page code for Yandex metrics?

Question

Joomla

Good afternoon kittens! Sorry for the noob question, not my profile. There is a site on which you need to tie Yandex.metrics, namely setting goals. This is an event that fires when, for example, the user clicks on the button I need. At the same time, statistics on how many people clicked on this button come to your personal account. To do this, I need to change the button code (in my case, this is a link to the phone)

<li class="sp-contact-phone"><i class="fa fa-phone" aria-hidden="true"></i> <a href="tel:[phone]">(8182) 42 25 10</a></li>

adding a line like

onclick="ym(XXXXXX, 'reachGoal', 'TARGET_NAME'); return true;"

But I didn't find how to do it at all. The situation is aggravated by the fact that this info is configured in the shaper_helix3 template.

I understand that, most likely, I need to override this template in the right place by setting the code from Yandex. But the search in the template files did not bring success.
If suddenly someone came across, tell me, please, in which direction to dig?