That is the order number allocated to your account by Magix, your confirmation email would include this number which you can refer to if you have any issues with your purchase, ie. downloading, installation problems and the like.
As far as I am aware that number has no additional purposes, the confirmation email would also include the activation serial numbers for the products purchased.
If it is not there contact Magix via the sales@magix.net email address quoting your order number. This is the public user forum so there are no Magix staff here to deal with your query.
This is a public forum, please do not post order numbers, serial numbers or any other personal information in the forum - you may lose control of your product.