At the end of a pattern it will say finish off or fasten off, both essentially mean the same thing, cut your yarn and end your work. It is the process to end your work that can get some discussion. No one really talks about it, as many are afraid that they may not being doing it correctly and they don’t want anyone to know. So this gets discussed in small private groups that people do not feel judged in, or when a brand new crocheter asks the question to a large group.
The two most common I have found in my discussions are to complete the stitch, leaving 1 loop on the hook, cutting the yarn and pulling through this one loop. This does leave a slight “bump” at the end of your work, because in a sense you are creating a knot. I will be honest, this is the approach I most often use, I like to feel that the end will not come undone, basically it is a piece of mind for myself.
The second is to finish the last stitch, cut the yarn and pull it through the last stitch. This is the method used when working an invisible join, and l feel it can have a really nice finish off, if you are prepared to weave in your ends immediately. There is the benefit of not having any extra little knot at the end of the work, giving a soft even feel across the entire fabric.
There really is not right or wrong way to finish off, it is a matter pf personal preference. You may feel that in some instances a different finish can benefit your work, and that is fine. As always as long as you are happy with your work, that is all that is important.