iFrame refresh

I would like to know if it is possible to refresh an iframe on an “onClick event”

If you had searched the forum before posting you would have found code examples for refreshing the iframe.
https://www.wix.com/corvid/forum/community-discussion/refresh-iframe-every-5-seconds
https://www.wix.com/corvid/forum/community-discussion/refresh-an-iframe-every-5-sec

If you read correctly, I am not trying to refresh my iframe automatically. I want it to be done only by clicking.

Yes and if you had read the code examples on that page you could take the code and adjust it to suit your own page.

With this one here you can take it out of the pages onReady function so that it does not run when the page loads and then you add it to a button onClick event handler function and adjust the code to suit your own needs.
https://www.wix.com/corvid/forum/community-discussion/refresh-iframe-every-5-seconds

With the other one you can write the code into the html iframe itself which this example is showing you how to do it, all you would need to do then is to look up html code and work out how to add a onClick event handler function into the code itself.
https://www.wix.com/corvid/forum/community-discussion/refresh-an-iframe-every-5-sec
https://www.w3docs.com/snippets/html/how-to-make-button-onclick-in-html.html
https://www.w3schools.com/tags/tag_button.asp

Or you look at the HTML Component and you use code to pass data from the page to the html component or from the html component to the page as described here.
https://support.wix.com/en/article/corvid-working-with-the-html-element
https://www.wix.com/corvid/reference/$w.HtmlComponent.html

Finally, you might want to make sure that your forum post header actually matches your question too then, as your title simply states that you want to refresh your iframe whereas your body text is talking about refreshing on button click, which are two different things.