Note: Microsoft no longer hosts these direct downloads on their public "Download Center" for Office 2016 (as it is out of mainstream support). However, there are still legitimate ways to obtain the 64-bit Arabic pack.
If you cannot obtain the official Volume License for the , consider these options:
After installation, Office will not automatically switch to Arabic. You must configure it manually.
To install the Arabic (64-bit) language pack for Microsoft Office 2016 , you must Language Accessory Pack