Here you will be able to describe the sales. The characterization of a sale can be done at the time of creating a sales order. Just like customer tags, you can make sales tags. A sales tag column will appear in the sales window while taking orders, if created previously, you will only need to select a tag. You can make the sales tags mandatory or optional. If mandatory without the tags an order can not be saved.
To make it mandatory or optional go to setup->preferences->sales prefs.
Go to Setup then Sales Setup and now Sales Tags
Enter the tag name and submit.