How to insert value for relate field through POST API in postman

Hi,

When I am creating a new record in Account module ,How to insert data or value into "relate type field" through POST API in Postman? If any random value (new name) I insert, wont update in response.

As far as I understood ,through UI we are selecting contact from existing contact list (here i used contact name as relate field in account from contact).It wont take new name.

please provide some solution ,it would be helpful for me .

Thanks in advance,

Shubhangi