I'm still getting an error. For company id -> ERR: Cannot read properties of undefined (reading 'company_id')

And for moving the invoice_policy and tic_category_id -> ERR: Field "invoice_policy" does not exist in model "product.product"

he invoice_policy and tic_category_id fields might be defined in related models or inherited models.
To resolve these errors and successfully move or hide the fields, you need to find the correct model where these fields are defined and update your code accordingly. Here's an example of how you can modify the code:

record id="view_product" model="ir.ui.view">
field name="name">custom.product.product.form.inherit</field>
field name="model">product.template</field>
field name="priority" eval="6"/>
field name="inherit_id" ref="product.product_template_only_form_view"/>
field name="arch" type="xml">
xpath expr="//page[@name='general_information']" position="inside">
field name="barcode" position="replace"/>
/xpath>
xpath expr="//page[@name='general_information']/group[@name='general_info_group']" position="inside">
field name="invoice_policy" position="replace"/>
field name="tic_category_id" position="replace"/>
/xpath>
/field>
/record>

In this modified code:

The model field is changed to product.template to match the correct model where the fields are defined.

The inherit_id is set to product.product_template_only_form_view to inherit the form view specific to the product.template model.

The <xpath> expressions are adjusted to target the correct locations within the view hierarchy, considering the new model and view.

sorry, now i'm getting this error -> Field "invoice_policy" does not exist in model "product.template"

apparently it still doesn't exist. this is odoo16v if it helps

model in Odoo 16, you can use the following approach:
record id="view_product_template_form" model="ir.ui.view">
field name="name">custom.product.template.form.inherit</field>
field name="model">product.template</field>
field name="inherit_id" ref="product.product_template_only_form_view"/>
field name="arch" type="xml">
xpath expr="//field[@name='barcode']" position="replace">
!-- Your modified barcode field -->
/xpath>
xpath expr="//field[@name='tic_category_id']" position="replace">
<!-- Your modified tic_category_id field -->
/xpath>
xpath expr="//field[@name='company_id']" position="attributes">
attribute name="invisible">1</attribute>
/xpath>
/field>
/record>
In this example, I have assumed that the barcode and tic_category_id fields exist in the product.template model. You can modify the code inside the <xpath> tags to define the modifications you want to make to these fields.

Make sure to update the model attribute in the <record> tag to match the target model for your customization.

the fields are now hidden, thank you for that. however, i still can't use invoice_policy and tic_category_id

Can i use xpath to show the field?

yes,you can

how can i use xpath to show the invisible field?

<style type="text/css">
p.p1 {
margin: 0.0px 0.0px 0.0px 0.0px;
font: 13.0px 'Helvetica Neue'
}

p.p2 {
margin: 0.0px 0.0px 0.0px 0.0px;
font: 13.0px 'Helvetica Neue';
min-height: 15.0px
}
</style>
<style type="text/css">
p.p1 {
margin: 0.0px 0.0px 0.0px 0.0px;
font: 11.0px 'Helvetica Neue'
}

p.p2 {
margin: 0.0px 0.0px 0.0px 0.0px;
font: 11.0px 'Helvetica Neue';
min-height: 12.0px
}
</style>
<style type="text/css">
p.p1 {
margin: 0.0px 0.0px 0.0px 0.0px;
font: 13.0px 'Helvetica Neue'
}

p.p2 {
margin: 0.0px 0.0px 0.0px 0.0px;
font: 11.0px 'Helvetica Neue';
min-height: 12.0px
}

p.p3 {
margin: 0.0px 0.0px 0.0px 0.0px;
font: 11.0px 'Helvetica Neue'
}
</style>
<p>&nbsp;&lt;xpath expr=&quot;//field[@name=&apos;invoice_policy&apos;]&quot; position=&quot;attributes&quot;&gt;</p>
<p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&lt;attribute name=&quot;invisible&quot;&gt;0&lt;/attribute&gt;</p>
<p>&lt;/xpath&gt;</p>

This code doesn't display the invoice_policy

i need to use xpath instead of field since i am having an error that the field doesnt exist

xpath expr="//field[@name='invoice_policy']" position="attributes">
attribute name="invisible">0</attribute>
/xpath>