@Jennifer3217 Regarding key codes- many hosts do like to send them out day-of, for the reason you state, but as someone who hates last minute stuff when I travel, I would not be okay with check-in info given so late.
As a home share host, I meet guests personally and they get a physical key. But what you can do, which a lot of hosts do, is only program the code to activate at check-in time so guests can't arrive before then and get in early. And using the last four digits of the guest's phone number, rather than random numbers, makes it easy for them to remember.