I'm from Saudi Arabia , Can I order Mac pro Online ?

Sales and service are provided by Apple-Authorized resellers in Saudi Arabia:

https://locate.apple.com/sa/en/

Buying direct from an Apple Online Store requires a credit card issued in that country, and Apple does not ship outside of that country. For example, you can only buy from the US Apple Online Store for delivery in the US, and by using a US credit card or US bank account.