new with some questions

[Rami Yacoub]

Hello every body,

I'm still new in Prestashop it's my first time I use it and I find it amazing CMS, but I have somethings want to modify 

1-how  can I change the currency position for example ($10) to be (10 $)

2- how to modify the shipping address form "I only want the user to add his phone, with governate (from my country) and address in text area" 

3- also I want to remove the invoice address form, I have only cache on delivery 

I will be very thankful for any help

Thanks