Avery 6450 labels are 63 per sheet, 1 inch round. You can design these using the 6450 template in Avery Design & Print Online.
You can also use a template built into Microsoft Word or download an Avery 6450 template for Word, Photoshop or Illustrator.
Here's some information on recommended printer settings. Following the print instructions carefully is important because there are so many small labels on this sheet.
If you want more information about a specific Avery label, search for the product number on avery.com.