I am hoping someone here can help me. I would like to run my Digitech Vocalist Live FX Processor through my Boss RC-300 Looper. I am not Tech savvy. Is it possible to do this and if so how?
Save for some unusual vintage pedals, you can connect any effect to any other effect, usually simply with a single ¼" patch cable. Vocal processors are a bit of a special case because their connectors are by default XLR, but the Vocalist Live seems to have also a line-out and the RC300 also an XLR input, so you can choose either XLR or ¼" – doesn't really matter.
Now, just because it's possible doesn't mean it's also musically useful. Lots of effect combinations interfere rather badly. But there's no reason to fear that here. For what it's worth, the combination of vocal processor and looper is nowadays quite common; in that light you may well try it.
I personally have a strong dislike for most of what such vocal processors do (pitch “correction” destroys much of the nuances of a good vocal performance, and harmonizers never come close to the intimate resonance between actual multiple human voices), as well as looping in general (which not only makes the musical material predictably repetitive, it also prevents natural tempo development). But that's just my taste, evidently many people disagree about this, and anyway this doesn't really get worse if you connect both together vs either effect on its own.
So, to answer how to do it... well, you connect your mic into the Vocalist as usual, then an XLR cable into the output and that into the looper's input. Alternatively, connect a ¼" cable to the Vocalist's line output and into the looper's input.