How to archive folder in Outlook
To customize AutoArchive features for the specific folder, do the following:
1. Right-click in the specific folder and choose Properties... in the popup menu:

2. In the Properties dialog box, choose the AutoArchive tab:

3. You can specify how you want to archive messages in this folder.
If necessary, you can specify archive settings for every folder that you want.
See also the tip How to automatically archive emails in Outlook.