add county to zip code

H i Team,

Currently, For zip code 31016 there is only one county named 'Monroe' in the system. We would like to add more counties to the same zip code. I have attached a screenshot where for same zip code we see below counties. We are using Vertex.

We are trying to add 'Crawford' county to 31016. When we google search these are the results showing for Crawford

"Some zip codes in Crawford County, Georgia include:31008, 31030, 31052, 31078, 31066, 31050, and 31016".

But in system we are not able to find Crawford county for any of the zipcode.

Please let us know, How to achieve this.

Thanks