If your school doesn't use Avery brand labels, there's no requirement to specifically buy them. Most printable label formats use the same sizes as Avery. You'll just need to find out the size of the labels you usually use.
- Look at the packaging that came with your labels, or the appropriate brand's website to find out the length and width of your labels.
- Go to Avery's website to find which size has the same length and width and number of labels across and down per sheet as your labels.
- Once you've identified the right option, choose this Avery option in Arbor. Your labels will be printed onto your own labels at the right size.
You can also try to print a template using the correct one from this site https://www.a4labels.com/