How to update the custom fields added via key user extensibility in mass upload

[TG1]

I have created two custom fields in billing document header level. 1. Customer GRN document no and Customer GRN date.

This data is available with us after the Goods receipt at customer side. 

My question is  can we mass update these fields. if yes then how can we update.

[Jerry_Lowery]

Hi TG1,

I am unfortunately not an expert on Billing but I checked available APIs that are enabled for custom fields- I don't see they do update (see Read and Create). I don't see an app that does mass change of billing doc (besides mass update of output items)

Could you provide us some more info about your requirement?

Does it need to be on the Billing Doc? as you mention the info is available only on goods receipt, could you update the delivery? I know there are APIs available to update the delivery custom field after the goods receipt.

Will all the documents have the same value for the custom field?

is it something that could be sent with the GR, can you do the GR via API?

Thank you

Jerry