EDGARROJAS

The only wordpress invoice system that has its own android app so you can create invoices in your computer or directly using your phone.
Features 
* Client, services and invoice management 
* Create invoices in your computer or in your phone 
* Email the invoice to your client 
* PayPal support (so your clients can pay you using your site directly)
How to use this plugin 
1.- Install this plugin 
2.- Install the app “Invoice For WordPress” in your phone: https://play.google.com/store/apps/details?id=com.rednao.invoiceonthego 
3.- That’s it!
Features
<ul>
<li>Create invoices and services.</li>
<li>Manage clients</li>
</ul>

Invoice On The Go

Create invoices anywhere (and in seconds) using your phone!

exentric

Add invoice functionality to checkout page and adds editable fields to user profile and to order page per Greek standards
<h4>Features</h4>
<ul>
<li>Ads required fields for invoicing in checkout page (vat, tax office and profession)</li>
<li>Choose if you want the Company Field to be moved to the invoice fields </li>
<li>Checks if user has asked for invoice and makes the fields required</li>
<li>Inserts the fields on back end user profile page, so admin can view or edit them</li>
<li>Displays field in admin order details, admin can pull them from user profile in case of phone order and edit them</li>
<li>Includes invoice fields in emails send to customers</li>
<li><a href="https://dev.exentric.gr/free-version/" rel="nofollow ugc">DEMO of free version >></a>
</li>
</ul>
<blockquote>
Timologia for WooCommerce PRO 
 <a href="https://dev.exentric.gr/" rel="nofollow ugc">DEMO PRO >></a>
 This plugin offers a pro version which comes with the following features:
 – Coming Soon POL39 
 – Get VAt details from AADE in backend and create customer account 
 – Coming Soon PDF invoice with own numbering, PDF Receipt with own numbering 
 – Customers VAT gets validated against AADE tool and fields are filled in automatically 
 – CHANGE THE TEXT IN DROPDOWN FROM Yes – No, to whatever you want e.g. Invoice – Receipt 
 – Marks all fields with the required css 
 – Choose to move the company field with the timologio fields 
 – If you choose to move the company field it becomes required 
 – Customers VAT gets validated against the EU VIES tool 
 – IF the VAT fails the check, order will not proceed and customer will be notified 
 – If VAT is validated, the responce from VIES is recorded in the admin order screen 
 – Option to disable VAT validation 
 <a href="https://www.exentric.gr/web-design-blog/woocommerce/woocommerce-vat-validation.htm" rel="nofollow ugc">Upgrade to Timologia for WooCommerce PRO >></a>
</blockquote>
<h4>Requirements:</h4>
<ul>
<li>WordPress version: 3.5.1+</li>
<li>Apache version: 2.1+</li>
<li>PHP version: 5.4+</li>
</ul>

Timologia for WooCommerce

Add invoice functionality to checkout page and adds editable fields to user profile and to order page per Greek standards

Invoice On The Go vs Timologia for WooCommerce