what you need to do that would show an additional currency as on your test site

At you on a site works as to make me that too would work

@rsn
We used multicurrency plugin, but based on last info I have, this plugin does not work anymore. Service used to get and update rates (yahoo) is down.

and why on your site it works.
https://osclasspoint.com/demo/front/86
you should indicate that this module with boxes does not work

@rsn
It's not our plugin, we've just updated it's design to match theme.
It works because rates shown in plugin comes from another installation from 2017 or so.

@Pattaxoxo
MultiCurrency Plugin (old one, free) does not work since 2018, you have to use alternative, i.e.:
https://osclasspoint.com/osclass-plugins/payments-and-shopping/exchange-rate-multicurrency-plugin_i92