In the United States of America, the first state to do this was Oregon.
It has been subject to controversy. Some conservatives fear that more low-income working people will vote, diluting conservative influence, some Americans oppose changing the tradition of going to a polling place, some fear vote fraud, but others point out that more people will vote.
In the United Kingdom they are called Postal votes. There have been allegations of electoral fraud as the postal vote does not need to be sent to the voter's address but can be sent anywhere of their choosing.
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