Technically, to create a multilingual website, you can generate directories such as: www.mywebsite.com/fr or subdirectories such as: fr.mywebsite.com.
This second solution is preferable to distinguish the backlinks coming from foreign websites and separate your contents.
It seems that the physical location of the server hosting a website can give an indication to the search engines about the language to detect. However, this data is not crucial. Indeed, for example, many French webmasters prefer an American hosting with a service provider with more advantageous offers…
The technique itself remains the same as for any website: you have to focus on content and backlinks in the target language.