View Source

To download a single attachment from a page:

View the page.
Right-click the link on the attachment name, and select Save Link As, Save Target As or a similar option provided by your browser. This will open a 'Save' dialog.
Select the location into which you want to download the file and choose Save.

Related pages:

To download all the attachments from a page:

View the page.
Choose the Download All button at the end of the page to download a zipped file of all the page's attachments.

Notes

There is no permission that controls the downloading of attachments. See an article in our knowledge base about disabling the download of attachments.
Confluence does not supply an option to download all attachments from a space. See the closed feature request: