Somewhere around the fiftieth product, generating barcodes one at a time stops being a minor annoyance and starts eating a real afternoon. That's usually the point a shop or warehouse looks for a bulk option — and it's worth setting up properly rather than as an afterthought.
Prepare your list before you generate anything
A clean spreadsheet with one product code per row, in the exact format your barcode type needs, saves far more time than fixing errors after the fact. Duplicate or malformed codes are the most common reason bulk batches need to be redone.
Generate once, export as a sheet
Rather than downloading individual image files, export the whole batch as a print-ready label sheet or a ZIP of individual files — whichever matches how you'll actually print, whether that's a roll of thermal labels or a full A4 page of stickers.
Spot-check before printing the full run
Pick five or six barcodes at random from a large batch and scan them before committing to hundreds of physical labels. It takes two minutes and catches formatting issues that are much more annoying to fix after printing.
Keep the source list as your record
The spreadsheet you generated from doubles as your inventory reference — save it somewhere your team can find it later, rather than relying on the printed labels alone to remember what number belongs to which product.