Hi Mona,
After your file your provisional patent application you will have
12 months (1 year) to decide if you want to file in other countries.
You can either:
(1) File a new application in each country you want protection (for example you could file in the US, Canada, Mexico, Europe, China, etc.), or
(2) File a single PCT Application
The PCT Application or an “International Patent Application” acts as a placeholder buying the inventor 30 months (2.5 years) to decide which countries they want to file in after that. Every major industrialized country is a part of the PCT.
More on this here:
https://patentfile.org/how-to-turn-your-provisional-patent-application-into-an-international-patent-application/