Making simple decals using your own computer and printer is not really difficult. Most any thing that you place on your screen can be turned into a decal although there are a few restrictions mostly having to do with certain colors. Fancier or more complex decals can be done though more challenging, how challenging depends on the software you have. how well you know it, your artistic skills and how innovative you are.
For modelers, making your own decals frees you to make signs, logos, etc that are not available or a best mean an expensive one of a kind custom job by a commercial supplier. Once you've placed something on your screen printing[printing?:printing cutting finishing solution] it on some kind of paper[paper?:paper sample maker cutting machine], making it into a decal, an overhead, a tee-shirt iron on, your own railroad letterhead, box labels, bad order forms, car cards etc is predominately a matter of the media you print[print?:printing image graphic cutting solution] it on. If a commercial decal is available I would use it, as it saves time and potentially money.
We will start with Media & Printers, then Software, then Making Decals and Other Things, followed by live creations. My suggestions will mostly be based on DOS based products, HP printers and software that I have. There are other software packages, printer and media suppliers that are suitable for these purposes. You probably don't have the same things I have so look for similar programs, features, and tools on your system.
