Hi,

To achieve the customization you're describing in Odoo 15, you can follow these steps.

1. Create a Custom Module:Create a new custom module to handle the customization. You can create a module structure with the necessary files such as __manifest__.py, __init__.py, and your main module file.

2. Define the New View:
In your custom module, create a new XML file to define the modified product form view. You can use the inherit_id attribute to inherit from the existing product form view and then customize it.Example:

<record id="product_template_form_view" model="ir.ui.view">
<field name="name">product.template.form.inherit.custom.model</field>
<field name="model">product.template</field>
<field name="inherit_id" ref="product.product_template_form_view"/>
            <field name="arch" type="xml">

                     <!-- Remove the entire 'invoicing' tab -->
<xpath expr="//page[@name='invoicing']" position="replace">

                </xpath>

                      <!-- Remove the entire 'Purchase' tab -->

                <xpath expr="//notebook/page[@name='purchase']" position="replace">

               </xpath>

                      <!-- Remove the entire 'standard_price' field -->

<xpath expr="//field[@name='standard_price']" position="attributes">

                        <attribute name="invisible">1</attribute>

                </xpath>

            </field>
 </record>

3. Update the __manifest__.py File:In your __manifest__.py file, make sure to include the new XML file:
Remember to adapt the XML code and file names according to your specific requirements. 

Hope it helps

I'm assuming you aren't a developer and want to do this from the front-end.

It's easy to do in Odoo studio!

Or with a little knowledge of Odoo XML you could create a new Form View that only contains the fields you need, and in one tab. Then change the Windows Action to use this new Form View and not touch the standard one.