Theres a lot of online training.
You can do TAFE courses like Retail certificate II & III which are short and simple to do, takes roughly 5 months and is generally 2 days a week depending on your location and availability in your area. Another is- Skills for work and vocational pathways- Retail context, which is another short course you can do in conjunction with the Retail course and is normally 1 day a week and you will finish the same time as the Retail course. You do not have to do these to get the job but it shows your interest in customer service and retail.
Not that i'm aware of