I need to fill some field(Doctype A) to some field(Doctype B)

[makarand_b]

@Leonel_Gonzalez,

please check Problem fetching values to child table after update - #4 by makarand_b
or in
User Manual https://frappe.github.io/erpnext/user/manual/en/customize-erpnext/custom-scripts/custom-script-examples/custom-script-fetch-values-from-master

Thanks, Makarand