We recently had released the app on App Store for iPhone and iPad but once the app got published we do see the Mac OS support and we are even able to download the app in our MacbooxandiMac`.
Is there a way to restrict this or apple does do this automatically as we haven't configured anything for Mac OS?
The whole point of M1 Macs is that they run iPad apps natively. OK, maybe not the whole point, but it's a major part of the meaning of an M1 Mac: its processor is an iPad processor so its apps can be iPad apps.
If you don't want your iPad app to be downloaded to an M1 Mac, you need to opt out. You can do that on the Pricing and Availability page of your app's entry on App Store Connect:
Note the checkbox. It is checked by default. Unchecking it is up to you. You didn't uncheck it, so your app was downloaded to some M1 Macs.