Discuss the various aspects of heat press technology. Transfer paper, inks, plastisol transfers, vinyl cutters, printers, commercial usage, durability, suppliers, etc.
There's not really a specific rule on trimming. It will really depend on your design. On opaque transfers, using a CAD cutter and "carrier" tape might help.
For light transfers you don't need to trim all the way to the edge of the design. Within about 1/8" from the edge should be fine, and you can leave the letters connected.
I think they may be asking if you had, for example, a line of text a few inches SEPERATE from a picture on a shirt? Assuming this is the question -
We leave seperated pieces like this connected by a thin line of transfer paper, maybe 1/4" thick or so. This keeps the spacing correct, let's us line it up more easily, and really isn't very noticeable on white or ash.
However, on white or ash t-shirts, it is barely noticeable at all with any good transfer paper. If you need to do darker shirts, you should probably be looking at another method such as plastisol transfers or vinyl.