How to enable feature to parse content in brackets []?

Hello,
i write a plugin at the moment and need the possibility to add something like this to a site or post: [younameit] – this value in brackets should then be parsed by the plugin and content – based on the post id – should be generated.

Can you tell me how i can tell my plugin that content with [] is important and should be parsed. How do you call this in the correct terms?

Thanks!