Your sign supplier will have a "standard" inexpensive application tape. It will do OK for most jobs, especially in-house jobs. If you are making decals for customers to take or for you to take to installations, you may have better results with something like R-Tape's RLA-4075 which has "release liner adhesive", meaning the application tape will stay stuck down to the empty release liner instead of lifting up and curling (and then getting stuck to the other decals while being transported)