A vinyl decal is cutout of solid vinyl, it's not a sticker, so you can't just peel it off the paper and stick it on something, it has be moved from paper to surface by transfer tape.

Decal with transfer tape.

Transfer tape is the clear coating on top of your decal.  The intent of transfer tape is to pull the decal off the paper and transfer it to your intended surface, then the transfer tape is removed and only the decal remains.

The transfer tape we use is marketed as extra tacky, meaning it should stick pretty good to the decal and help move it.  BUT sometimes the decal sticks to the paper better than the transfer tape sticks to the decal and we have issues. 

Like the next pictures, the transfer tape picks up some of the decal or part of the design but some of it stays on the paper. 

First 2 pictures show a part left behind. The third is more damaging since the design could be torn apart if not fixed and the reason you shouldn't just peel the design off without checking it.

So how can you avoid damaging the decal? First, you want to do what the above pictures are doing, slowly peel the transfer tape up and make sure the decal STAYS on the transfer tape.

Next, if it looks like anything above.. STOP, put the transfer tape back down and do this. Squeegee the top really good with a stiff card (credit, ID, or an actual stiff squeegee)

Then check again, if at any point it sticks to the paper, put it back down and squeegee again, or you can also push good on the spot with your finger.  It's a hassle but that means the sticky side of the decal is doing a good job of being sticky.

NOTE: We do this before it leaves our location, but going through the mail or environmental factors may cause it to happen on your end too.

What you should see is like this.

These issues can be caused by the characteristics of the decal itself, humidity, heat or other factors as it moves through the mail system.  Gold vinyl and matte decals are the worst at this. But this is one method you can use to make sure your decal works for you.

Hope this helps you.