I assume that you do have Pages on the Mac or you wouldn't be asking how to do this ......
You can use iOS file sharing to send the documents back and forth. You can use iCloud as well, if you have an iCloud.com account set up and if you are using iCloud on the iPad.
This talks about file sharing.
With iCloud - any work that you do in Pages on the iPad will sync to your iCloud account and you can open Safari on the Mac - go to your iCloud.com account in there, click on the iWorks section, click on Pages - and then access all of your files in there. You can download the file to the Mac, edit it and then upload it again by dragging the file back into the browser window.
When you launch Pages again on the iPad, the edited file will appear in the documents window.