Enable Archiving for Mailboxes

You can enable the mailboxes so that archiving starts immediately, that is, with the next run of the Exchange Mailbox Task.

Alternatively, you can enable the mailboxes but set them so that there is no archiving until the individual users turn it on.

When do you want archiving to start:

Immediately, using the default archiving settings. Select this to start archiving from the mailboxes with the next run of the Exchange Mailbox Task.
User decides. Select this to let the user choose when to start archiving and to give the user time, if necessary, to change the archiving settings. For example, the user could choose different Retention Categories for different folders, rather than use the default Retention Category that you have selected.

Select the archiving setting you want and then click Next to continue.