@EtienneOliveira In Settings>System>About on each device, what Roku account email address is each linked to? (I am guessing, based on what you described seeing, that these are linked to two separate accounts.)
As Danny mentioned earlier, Search from the Home screen is only currently available in select regions on the Roku platform. If you created an account in the US and linked your device to it, then took your device to another region, you may see 'Search' on the Home screen as the device is linked to a US account, however, many of the channels/services will likely not work as intended as they may not be available in that location.
You'll want to ensure that you create a Roku account in Brazil, and link your devices to that Brazilian Roku account in order to see the currently supported features and channels for your device in that region.
In order to move a Roku device to a new Roku account, you will need to factory reset the Roku device from Settings>System>Advanced system settings>Factory reset, then go through the process of linking the device to your Brazil Roku account.
I hope that helps clarify! Let us know if you have any other questions we can help answer.