I have 7 languages installed in my website, but when I try to display content in one country, it shows in another country.
How can I change the options?
For example, I want to display content in country #2, but it shows content for country #5.
Joomla has a core language plugin that you can find among plugins: Joomla admin->extensions->plugins->System - Language Filter
In this plugin you can set automatic language change for the front-end of your site based on the visitors' browser's language settings (in language selection for new visitors setting). It's just self explanatory:
And since Joomla 3.7 you can create content in different languages using the great associations feature of Joomla (with the Multilingual Associations component and the associations tab in article edit page). Full and quite clear tutorial is here: https://docs.joomla.org/Special:MyLanguage/J3.x:Multilingual_Associations
Using the language filter and the Multilingual Associations component you cannot really have problem with any languages (if you have translators of course). And the component is also quite clear and easy to use.