When tagging clothing for sale in your store, your biggest goal shoud be to avoid poking the tag gun needle directly through the fabric where there is potential to leave a visable hole in some fabrics.
Here are some ways to achieve that goal.
1. Use an existing tag in the neckline and insert a 3" fastener.
2. Tag at the sleeve cuff inside on the seam allowance. Use a 3" fastener.
3. Tag pants, shorts, or skirts between the waistband and body. Use a 2" or 3" fastener.
4. Tag lined jackets in the sleeve lining using a 3" fastener.
5. Use short fasteners, 1/4" or 1/2 for undergarments to keep the tags snug against the article