Enable Metafield's "Read and Write" access

When you have error messages like

"Customer Account access is not enabled for this metafield. Enable Read and write in Shopify admin."

This metafield is read-only for customers. Change access to Read and write in Shopify admin."

then please refer to this article.

From

Shopify admin → Settings → Metafields and metaobjects

Select metafields definition owner type.

As an example, we select Customers metafields.

Then change the Customer Account API Access to "Read and Write"