In my country:

• We have a mandatory national ID
• Having it automatically registers you as a voter after 16 y.o.
• Voting is mandatory between 18 and 70.
• We vote on Sundays to ensure everyone can go.
• Voting in always in person. We usually use schools to that end, windows are obscured to ensure secrecy.
• We record who voted following the electoral registry. Only the last issued national ID is valid to vote.