Customized pos send data to sales invoice field


Hi! How can I send the value entered in my customized field in POS to Sales Invoice field? Thanks a lot. Code below.
make_user: function () {
var me = this;
this.print_format_input = frappe.ui.form.make_control({
parent: this.page.main.find(".pos-bill-toolbar-user"),
df: {
fieldtype: “Link”,
options: “User”,
fieldname: “ph_assistant”,
placeholder:“Select Pharmacy Assistant”,
only_select: true
},
parent: this.page.wrapper.find(".party-area-user"),
only_input: true,
});

 this.print_format_input.make_input();
	 $(this).find(".party-area-user").val("hbh")
},