Where to add_filter in theme functions.php?

I am new to WordPress and want to make some changes in the content of a plugin page. I have found out that the same can be done using

add_filter

I have the filter value for the plugin content that I want to change. I am using the storefront theme. So I open the storefront_functions.php , but I am not sure where to add the code snippet.

Seeking guidance/suggestions regarding the same.

Thanks