The price tags in QuickStore are hard coded to ensure that the various elements fit properly on the given size labels. This being the case, there are no options for rearranging the information on the labels or selecting different information to print*, and only the label sizes selectably in File > Printer Setup > Price Tags are available.**
If you do need to use a different label size or add different information to the label, you would need export the item list (File > Export > Inventory) and then use that .csv file as a data source for a label created in other software, such as Wasp Labeler, which would need to be purchased separately.
*The one exception is that if you are using the Pro or Enterprise version, you can define multiple price levels for each item, and set the tags to use the second level as a "Compare At" price on the labels. That option is set in Setup > Store > Update Store Settings > 4. Pricing.
** For reference, the sizes, based on type of printer, are:
Thermal printer - 1.25" x 1.0", 2.25" x 1.25", 2.25" x 1.25" (Tag Stock), and Jewelry Tags 2.20" x 0.50"
Laser printer - Avery #5161 (4" x 1"), Avery #5160 (3" x 1")