Creation by link autofill field in new doc

I have a doctype “IP public” with a field “ip_customer” and one “ip_resource” the first one link to a Customer the second one to a Serial No.
The goal is when clicking on ip_resource and made a new doc autofill the field customer in new Serial No bringing the information in ip_customer.

Reading in the forum i have read that there is add_fetch, i tried it but don’t work

Thanks for your time

Thanks for your time,
I do not understand where to enter the field name of the second doctype. Is there a way to do it without using a button, but to create it starting from the link?

Define your use case with details and screenshot to understand easily.

Does this Serial No field have the customer value ? You can try this method for your case :-

Read this and see if it helps you. Check that image in post and you will get the idea.

Here are the screens:

the arrow point ip_resource, the field “Clienti” is ip_customer:

Creating new doc starting from an ip doc with customer already full:

I would like the new document being created to suggest the client already by taking it from the ip from which it started (field customer):

very sorry for the late reply

Do you wish to fill this field Customer when Serial No is selected, right ? If I am getting it right - then I assume that while Serial you also added the customer.

Thanks for the reply
Yes it’s correct, fill customer field in serial no when select new serial no, customer in original doc is already full.

@alberto_solaro have you got solution for this? i need similar one