Fetching doc.submitter onto Printformat

Hi, I am wondering about how to fetch the doc. submitter onto the print format. Can anybody advice? Thank you!

Can you explain with the help of an example?

Dear Mr. Rmehta,

This is the example of our PO’s print format. Towards the bottom of the print format lies two regards columns with their user roles and signature attached. (I apologize that the wordings are all in Thai). The left column is supposed to be the person who issued the purchase, so here {% set u = frappe.get_doc(“User”, doc.owner) %}

is used for fetching that data. To the right column is supposed to be the approver, so we used {% set u = frappe.get_doc(“User”, frappe.user) %}. But by using frappe.user sometimes when other user other than the approver prints the document their user will appear in the field instead. So I wonder if instead of using frappe.user, is there a way that we can always fetch the document submitter whom is supposed to be the approval of purchase data on the print format.

Thank you for your kind advice.
Chonlapob J.