diff --git a/addons/portal/views/portal_templates.xml b/addons/portal/views/portal_templates.xml
index caa03a627a3..bb1d62fffc4 100644
--- a/addons/portal/views/portal_templates.xml
+++ b/addons/portal/views/portal_templates.xml
@@ -376,17 +376,23 @@
                             </div>
 
                             <div class="clearfix" />
-                            <div t-attf-class="form-group #{error.get('company_name') and 'o_has_error' or ''} col-xl-6">
+                            <div t-attf-class="form-group mb-1 #{error.get('company_name') and 'o_has_error' or ''} col-xl-6">
                                 <label class="col-form-label label-optional" for="company_name">Company Name</label>
                                 <!-- The <input> is replace by a <p> to avoid sending an unauthorized value on form submit.
                                      The user might not have rights to change company_name but should still be able to see it.
                                 -->
-                                <p t-if="not partner_can_edit_vat" t-attf-class="form-control" readonly="1" t-esc="partner.commercial_company_name" title="Changing company name is not allowed once document(s) have been issued for your account. Please contact us directly for this operation."/>
-                                <input t-else="" type="text" name="company_name" t-attf-class="form-control #{error.get('company_name') and 'is-invalid' or ''}" t-att-value="company_name or partner.commercial_company_name"/>
+                                <input type="text" name="company_name" t-attf-class="form-control #{error.get('company_name') and 'is-invalid' or ''}" t-att-value="company_name or partner.commercial_company_name" t-att-readonly="None if partner_can_edit_vat else '1'" />
+                                <small t-if="not partner_can_edit_vat" class="form-text text-muted d-block d-xl-none">
+                                    Changing company name is not allowed once document(s) have been issued for your account. Please contact us directly for this operation.
+                                </small>
                             </div>
-                            <div t-attf-class="form-group #{error.get('vat') and 'o_has_error' or ''} col-xl-6">
+                            <div t-attf-class="form-group mb-1 #{error.get('vat') and 'o_has_error' or ''} col-xl-6">
                                 <label class="col-form-label label-optional" for="vat">VAT Number</label>
-                                <input type="text" name="vat" t-attf-class="form-control #{error.get('vat') and 'is-invalid' or ''}" t-att-value="vat or partner.vat" t-att-readonly="None if partner_can_edit_vat else '1'" t-att-title="None if partner_can_edit_vat else 'Changing VAT number is not allowed once document(s) have been issued for your account. Please contact us directly for this operation.'" />
+                                <input type="text" name="vat" t-attf-class="form-control #{error.get('vat') and 'is-invalid' or ''}" t-att-value="vat or partner.vat" t-att-readonly="None if partner_can_edit_vat else '1'" />
+                                <small t-if="not partner_can_edit_vat" class="form-text text-muted d-block d-xl-none">Changing VAT number is not allowed once document(s) have been issued for your account. Please contact us directly for this operation.</small>
+                            </div>
+                            <div t-if="not partner_can_edit_vat" class="col-12 d-none d-xl-block">
+                                <small class="form-text text-muted">Changing company name or VAT number is not allowed once document(s) have been issued for your account. <br/>Please contact us directly for this operation.</small>
                             </div>
                             <div t-attf-class="form-group #{error.get('phone') and 'o_has_error' or ''} col-xl-6">
                                 <label class="col-form-label" for="phone">Phone</label>
diff --git a/addons/website_sale/views/templates.xml b/addons/website_sale/views/templates.xml
index e20788c338b..17ab252640c 100644
--- a/addons/website_sale/views/templates.xml
+++ b/addons/website_sale/views/templates.xml
@@ -1453,14 +1453,20 @@
     <template id="address_b2b" inherit_id="address" name="Show b2b fields" customize_show="True">
         <xpath expr="//div[@id='div_phone']" position="after">
             <div class="w-100"/>
+            <t t-set='vat_warning' t-value="'vat' in checkout and checkout['vat'] and not can_edit_vat" />
             <t t-if="mode == ('new', 'billing') or (mode == ('edit', 'billing') and (can_edit_vat or 'vat' in checkout and checkout['vat']))">
-                <div t-attf-class="form-group #{error.get('company_name') and 'o_has_error' or ''} col-lg-6">
+                <div t-attf-class="form-group #{error.get('company_name') and 'o_has_error' or ''} col-lg-6 mb-0">
                     <label class="col-form-label font-weight-normal label-optional" for="company_name">Company Name</label>
-                    <input type="text" name="company_name" t-attf-class="form-control #{error.get('company_name') and 'is-invalid' or ''}" t-att-value="'commercial_company_name' in checkout and checkout['commercial_company_name'] or 'company_name' in checkout and checkout['company_name']" t-att-readonly="'1' if 'vat' in checkout and checkout['vat'] and not can_edit_vat else None" t-att-title="'Changing company name is not allowed once document(s) have been issued for your account. Please contact us directly for this operation.' if 'vat' in checkout and checkout['vat'] and not can_edit_vat else None" />
+                    <input type="text" name="company_name" t-attf-class="form-control #{error.get('company_name') and 'is-invalid' or ''}" t-att-value="'commercial_company_name' in checkout and checkout['commercial_company_name'] or 'company_name' in checkout and checkout['company_name']" t-att-readonly="'1' if vat_warning else None" />
+                    <small t-if="vat_warning" class="form-text text-muted d-block d-lg-none">Changing company name is not allowed once document(s) have been issued for your account. Please contact us directly for this operation.</small>
                 </div>
-                <div t-attf-class="form-group #{error.get('vat') and 'o_has_error' or ''} col-lg-6 div_vat">
+                <div t-attf-class="form-group #{error.get('vat') and 'o_has_error' or ''} col-lg-6 div_vat mb-0">
                     <label class="col-form-label font-weight-normal label-optional" for="vat">TIN / VAT </label>
-                    <input type="text" name="vat" t-attf-class="form-control #{error.get('vat') and 'is-invalid' or ''}" t-att-value="'vat' in checkout and checkout['vat']" t-att-readonly="'1' if 'vat' in checkout and checkout['vat'] and not can_edit_vat else None" t-att-title="'Changing VAT number is not allowed once document(s) have been issued for your account. Please contact us directly for this operation.' if 'vat' in checkout and checkout['vat'] and not can_edit_vat else None" />
+                    <input type="text" name="vat" t-attf-class="form-control #{error.get('vat') and 'is-invalid' or ''}" t-att-value="'vat' in checkout and checkout['vat']" t-att-readonly="'1' if vat_warning else None"/>
+                    <small t-if="vat_warning" class="form-text text-muted d-block d-lg-none">Changing VAT number is not allowed once document(s) have been issued for your account. Please contact us directly for this operation.</small>
+                </div>
+                <div t-if="vat_warning" class="col-12 d-none d-lg-block mb-1">
+                    <small class="form-text text-muted">Changing company name or VAT number is not allowed once document(s) have been issued for your account. Please contact us directly for this operation.</small>
                 </div>
             </t>
         </xpath>