Templates for Docmail can be accessed in the following location:
https://www.docmail.co.uk/templates.html
Documents can be added into Docmail as Microsoft Word (.doc or .docx), Rich Text Format (.rtf), Open Office (.odt) or Portable Document Format (.pdf).
You can only use PDF files if the document is to be printed exactly as supplied, with any personalised fields in it being set up as Form Fields.
With all other documents, you can type the merge tags into your document before uploading to Docmail.
Personalised means that Docmail will put the name and address on the document (unless you choose to select no address panels), and wherever you have used a merge tag in a document, Docmail will replace that field with the data provided in your spreadsheet.