You have addresses in a spreadsheet and a pack of label sheets. Here's the route between them that doesn't waste stock.
Look at the box for two things: the label dimensions and how many per sheet. Those two facts identify the layout completely, regardless of what product number is printed on it. Many different numbers share identical geometry.
Also check whether your sheets are US Letter (8.5 × 11 in) or A4 (210 × 297 mm). This matters: the templates are not interchangeable. If you're in the UK or Europe, you almost certainly have A4.
You don't need a perfectly tidy spreadsheet, but two things help:
Then select the columns you need and copy them. Copying from Excel, Google Sheets, or Numbers puts tab-separated data on your clipboard, which any decent label tool can read directly.
Decide what goes on each line. A typical address label is:
{Name}
{Street}
{City}, {State} {ZIP}
Two things worth getting right here:
Optional second address lines. Most address lists have an "Address 2" that's empty for most rows. If it's on its own line unconditionally, most of your labels get an awkward blank gap. A tool that collapses empty fields handles this automatically. Otherwise put it on the same line as something else.
Text size. Bigger than you think for anything a courier handles. An address that has to be squinted at gets misdelivered. If your text doesn't fit, the answer is usually a larger label layout, not a smaller font.
Before printing on real stock:
If it's off by a consistent amount in one direction, that's your printer's paper feed. Normal, and fixable with a calibration offset that you set once. If the misalignment gets progressively worse down the page, that's print scaling, and you need to fix the setting rather than the offset. More detail in why labels print slightly off.
Two practical notes:
Use up part-used sheets. You rarely finish exactly on a sheet boundary. Being able to start at label 14 uses up last week's remainder instead of wasting the top half of a fresh sheet. Over a year of weekly shipping that adds up to real money.
Feed sheets one at a time for small batches. Label stock is thicker than paper and more prone to double-feeding, which jams and wastes two sheets at once.
Save yourself the setup each time: keep a spreadsheet tab with your columns already in the right order, so the weekly job is copy, paste, print. And once you've found your printer's calibration offset, it doesn't change, set it once.
The same idea works on forms rather than labels: batch fill takes one PDF form and a spreadsheet, and produces a filled copy for every row.
Paste a spreadsheet, get print-aligned labels. With an alignment test sheet built in.
Try the Label Sheet Maker