Hi Ahmed,

By default the quotation and invoice PDF's are multi language.
Odoo looks at the customer set on the quotation/invoice. If the language set on the customer is not english it will print the report in another language. For example if I create a Dutch customer:

When I would assign this person to a quotation and would print it it'll be in Dutch:

The only requirement is that the translations are made for that language. If this is done you can do it all out of the box in Odoo.

Tip: You can handle the multi language product names and descriptions on the product form through the world globe icon:

Regards,
Yenthe