How does postal voting work in the USA?

Absentee voting in the United States, also known as “absentee voting” or “mail-in voting,” allows registered voters to cast their vote without having to appear in person at a polling station. The process begins with voter registration, which ensures that voters are registered as such in order to be able to participate in the postal vote. Applying for an absentee ballot is done online in some states, while others require a physical form to be filled out and submitted.
Once the application is approved, the voter will receive a mail-in ballot package that includes the ballot, voting instructions, and envelopes for the ballot and possibly for security and anonymity. The voter fills out the ballot paper according to the instructions, places it in the envelope provided and signs it to confirm the authenticity of their vote.