If your website has different pages aimed at people in multiple specific countries, you need to be using the “hreflang” tag on your pages. Google knows where its users are, and which language they’re searching in, and having this tag on your site can match the right people with the right page. Effectively, it’s saying: “these pages aren’t duplicate pages, they’re versions of the same page aimed at a different country or language”.
It would be used, for example, if you’ve got a single domain (e.g. a .com) which is targeting different countries and languages through subdirectories. But it’s useful even if you only have, for example, separate UK and US sections of the site in the same langauge.
Google’s background to the “hreflang” tag is here. It’s just a line of code, or a few lines, to be added to the page headers, and it shouldn’t take your website manager more than a few minutes to sort out. You can have more than one tag on a page if the page is aimed at more than one country.
One thing to be careful of is to ensure the country and language codes are correct. A really useful tool here is the hreflang Tags Generator Tool by International SEO Map.
There’s even more background here.