How do you save an attachment that you get with an email? It is really not a good idea to just leave them in your email folders, unless you are eventually going to simply delete the email with its attachment(s).
If you are using Windows Live Mail or or Windows Mail):
Open the email, right-click on the attachment, click Save As. Find the folder you want to store it in. Read this section to understand how to find where to put the file http://canadiantech.info/?page_id=104. You can change the name of the file (and you probably should) before you save it. If there are multiple files attached, you should do the same for each of them.
If the attachment is a document that you want to modify (edit), it is critical that you remember to save the document in a folder that you can find. If you simply click Save, it will be stored in a place you will never find. You must click Save As and navigate to a folder you can later find.
If you are using browser-based email (such as Yahoo, Gmail or Microsoft):
You will have to use the tools that come with that program. I will not go into them individually here, but at some point in the process, you will need to navigate to a folder on your computer to store it, and name the file. Keep in mind that if you are using these products, those emails and their attachments are NOT on your computer. The only way to get the attachments on your computer is the process partly described here.