When creating your campaigns, you can now set them up so that customers can only make a single donation or they can make recurring donations over a period of months or they can choose which they'd rather do.
Navigate to Tools - Fundraising and 'Edit' one of your campaigns. Under 'Donation Frequency', you'll now see this:
You must select at least one, but can select all four boxes if you wish. By selecting 'One Time' you permit the customer to make a single donation now. 'Monthly' permits the customer to set up monthly donations starting today. 'Quarterly' permits the customer to set up an automated donation every three months starting today. And 'Yearly' permits the customer to set up an automated donation every year starting today.
If you wish to only allow recurring donations for a campaign, simply leave 'One Time' unchecked.