deleted - already answered by others
No, how long you are allowed to stay depends on your nationality, and it's also at the discretion of the immigration officer.
But most people from western countries seem to get 90 days, and British citizens can get 180 days.
If they (who are they?) are asking for HKID then they are not willing to sponsor you but want someone who already has the right to stay here. If "they" are your future employer then you can't get sponsored by someone else and then work for them.
The length of time you are allowed to stay here varies from 14 days to 6 months depending on nationality (and at the discretion of the Immigration Officer as previously said). You are not allowed to work in this time.