These file types are not optimal, because not all computers or devices will be able to open them.
However, if you do need to link to a Microsoft Office file in your SharePoint site, you can upload it to the root Documents library.
Go to your site's home page and click on Site Actions, then select View All Site Content. The Documents library there should be set up to allow .doc, .docx, .xls, and .ppt files.*
*Contact DXA if you link to files that live in this folder and they still require login.