I recently sold an image that was published in a magazine in the UK and they want me to send them an invoice so payment can be made. This is my first time doing this, are there programs etc to produce one so I can do it up and send via email. Normally the magazine just send me payment but with it being in the UK they have a different system in place. Currently I have no apps or programs to do an electronic invoice but have no issues with buying an app for my mac to produce this. Any info or help at all would be much appreciated.