Thank you for the clarification, @hassain !
Following the API instructions you sent for creating a metafield on the Shop resource I’m encountering a new issue (does this require a new post? If so I’ll amend) where I sent a POST request to /admin/metafields.json with the params:
namespace=testMetafield&key=testKey&value=testValue&value_type=json_string //also tried value_type=string
and receive the following error:
"metafield": "Required parameter missing or invalid"
I’m using Postman and have verified authorization and removed all cookies on each request per @Jason in another thread regarding POSTs to the API.