'Android' is the operating system in a mobile phone.
Just as desktop computers can run on Windows or other operating systems such as Linux (or Apple's iOS if you buy a Macbook or similar) there are different operating systems used on mobile phones.
At one time you could buy mobile phones that used Windows as an operating system but Microsoft have now pulled out of the market.
So there are only two major operating systems for mobile phones left. If you buy an iPhone it will use Apple's own iOS operating system. iPhones are very expensive though, so the majority of people opt for something else and ALL other mobile phones use Android.
Just as there have been different versions of Windows over the years (such as Windows 98, ME, 2000, XP, Vista, 7, 8 and 10), there have also been different versions of Android added to mobile phones, as the operating system has gradually been updated. Up until the most recent versions (Android 10 and 11), all versions of Android had BOTH a number AND a name. So that, for example, Android 5 was called 'Lollipop', Android 6 was called 'Marshmallow', Android 7 was called 'Nougat', Android 8 was called 'Oreo' and Android 9 was 'Pie'.
Only the very latest Android phones (which are likely to be mega-expensive) use Android 10 or 11, so if you're looking for a budget phone you shouldn't expect to see it advertised as, say, 'Android 10'. In practice anything from Android 6 (a.k.a. Android Marshmallow) onwards will probably suffice, since most apps that you can download will run on any version of Android from 6 onwards. (Avoid any earlier versions of Android though, such as Android 4, which went through three incarnations as 'Ice Cream Sandwich', 'Jelly Bean' and Kitkat, or Andoid 5/Lollipop, as many modern apps won't run on such older versions of Android).
So, unless you want to spend money on an iPhone, any phone you might consider will definitely be running a version of Android. Just make sure that it's a reasonably recent one if you want to be sure that all available apps will run on it. (My own phone runs on Android 6/Marshmallow and I can see no reason to upgrade it).