I am trying to pass a parameter to a function that is using the LIKE '%name_in%',
I don't know how to use it...
the parameter is called 'name_in'
Your code should say:
... LIKE '%' || name_in || '%'
If name_in is inside single-quotes, it will mean the 7 literal characters 'n', 'a', 'm', 'e', '_', 'i' and 'n'.
You want to reference the variable called name_id, so keep the name of the variable outside the quotes.