Search function doesn't appear when not logged in

Hello.

It appears that the search function on our website is not available unless we log in, which is a problem because the site is mainly visited by people who don’t have a WordPress account. I’m not an expert in coding, and I imagine there is a way to manually insert the search button in our homepage, and if so, can you link me to a tutorial or guide of some sort?

The website I’m referring to is this one: http://vivereeconomia.it/
It’s in italian, but as you can see there is no magnifying glass anywhere to be seen.

Thank you in advance for your response.