module-vendor-notes/etc/adminhtml/system.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_file.xsd">
    <system>
        <tab id="shopkeeper" translate="label" sortOrder="999">
            <label>Shopkeeper</label>
        </tab>
        <section id="vendor_notes" translate="label" type="text" sortOrder="100" showInDefault="1" showInWebsite="1" showInStore="1">
            <label>Vendor Notes</label>
            <tab>shopkeeper</tab>
            <resource>Shopkeeper_VendorNotes::config_vendor_notes</resource>
            <group id="general" translate="label" type="text" sortOrder="10" showInDefault="1" showInWebsite="1" showInStore="1">
                <label>Vendor Notes Configuration</label>
                <comment><![CDATA[
                    <div style="padding: 10px; background: #f0f0f0; border-left: 3px solid #1979c3; margin-bottom: 20px;">
                        <strong>How to use Vendor Notes:</strong>
                        <ul style="margin: 10px 0; padding-left: 20px;">
                            <li>Click "Add Row" to create a new vendor note configuration</li>
                            <li>Enter the <strong>exact vendor name</strong> as it appears in the Vendor attribute (Stores > Attributes > Product > Vendor)</li>
                            <li>Enter your note text - HTML is supported for links and formatting</li>
                            <li>Notes will automatically appear on order pages when products with the matching vendor are in the order</li>
                        </ul>
                        <strong>HTML Formatting Examples:</strong>
                        <ul style="margin: 10px 0; padding-left: 20px;">
                            <li>Line break: <code>&lt;br&gt;</code></li>
                            <li>Email link: <code>&lt;a href="mailto:support@example.com"&gt;support@example.com&lt;/a&gt;</code></li>
                            <li>Website link: <code>&lt;a href="https://example.com"&gt;Visit Website&lt;/a&gt;</code></li>
                        </ul>
                        <strong>Managing Vendors:</strong>
                        <p style="margin: 10px 0;">To add or edit vendor options, go to <strong>Stores > Attributes > Product</strong> and edit the <strong>Vendor</strong> attribute (code: <code>vendor</code>)</p>
                    </div>
                ]]></comment>
                <field id="vendor_mapping" translate="label" sortOrder="10" showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Vendor Notes</label>
                    <frontend_model>Shopkeeper\VendorNotes\Block\Adminhtml\Form\Field\VendorMapping</frontend_model>
                    <backend_model>Shopkeeper\VendorNotes\Model\Config\Backend\HtmlArraySerialized</backend_model>
                    <comment>Add vendor names and their corresponding notes. The vendor name must match exactly as it appears in the product attribute.</comment>
                </field>
            </group>
        </section>
    </system>
</config>