Convert a doc document to a pdf with custom fields

We have two documents written using google docs. They are in plain spanish; 1. Service contract. 2. Bank SEPA document. Nowadays, we are filling the documents simply by editing the text on the documents. Now, we'd like the people in charge of sales, to fill in the documents just by adding the changing information on that documents in the corresponding fields. They are accounts bank data, addresses data, names, surnames... i.e. the regular data that you may found in a legal document. Finally, we need a button to save the filled form which must create the corresponding PDF. The very close documents are the following. In red are the fields that must be open to edit to the sales people; [login to view URL]