The most important point to remember about foreign patent filing is that before you even begin the process most foreign countries require you to have already filed your U.S. patent application. This has to be done before any public disclosure of the patent. Failure to do so would mean the loss of any foreign patent filing rights you had.
The US Filing date is the priority date when foreign patent filing. This priority right means that your foreign application will be given the same consideration as the application of a citizen of a member country who filed on the same date. The one year after filing the U.S. applies only to patents. Applications for industrial designs and trademarks need to be made within six months. The one year or six months is given because it is not logistically possible foreign patent filing to file on the same date in all of the countries of your choosing as you can see from this post on https://inspirationfeed.com/how-inventhelp-can-help-you-protect-your-invention/.
No State emblems of any member country may be used without express prior authorization. This prohibition also applies to any governmental organizations to which each State belongs. The application will be invalidated if there is improper use of any State emblem. When you are in the process of foreign patent filing the prohibition does not apply if there is nothing to suggest to the public that a connection exists between the applicant and the concerned organization and it was very well described in details on https://www.oddee.com/how-inventhelp-can-assist-new-inventors/.
When foreign patent filing, keep in mind that if you are granted a patent in one State, other States are not then also obligated to grant the patent. Each State is independent of the other. Also, if one State does not grant the patent, another State is not allowed to then deny someone who is foreign patent filing the granting of a patent because of the refusal.