Hi @Veronika124
I'm not the most technologically savvy person in the world, but have your considered using a keypad rather than a lock box?
You can generally have up to 6 codes programmed at a time - eg one for you, one for a cleaner or tradie, and then one for a guest.
We sue this system and change the code for each guest ( so they can't come back at another time and get back in). We use the first 6 digits of their mobile generally.
There are even keypads that can be controlled by a host remotely, so you can later codes without being physically present. We do have a very small lock box out of sight where we store a master key that can over ride the keypad if there is some type of emergency. So far have not had to use it...
I'm sure other hosts will add more specific info..
Cheers