Different types of plagiarism:
This needs little explanation because it is the simple - and totally wrong - act of attempting to pass off someone else's work as your own.
A little more strategic, this one - basically, you read a few texts, write down a few key sentences, change the words around, throw in a few quotes and citations to throw your tutor off the scent and 'hey presto' you have the perfect essay, right? Wrong!
Your tutors have read those books and seen this scam before. As with the first example, this type of plagiarism can only be done deliberately and it won't work.
Much as above, except that you've read and stolen from more books and 'patched' them together - easily detectable, deliberate and definitely deceitful, aided and abetted by online plagiarism!
Reading texts, selecting key phrases and then writing around them so that they seem different but are actually the same - this type of plagiarism is bluffing in the worst way because you are pretending ownership of ideas in order to fool others into thinking you know more than you do.
This type of plagiarism is within the 'grey zone' because all the sources used are usually correctly cited but the student needs to develop analytical skills to enable them to work effectively and produce work that is truly their own. So, this is still plagiarism but probably accidental and due to inexperience.
Using a copy of your own work
This one may surprise you because plagiarism of this type is not based on stealing the work of others but on reworking your own. You know the scenario, you have covered the topic or topics before, gained a good grade and are now short on time so you think you'll piece them together and produce a successful amalgam. Unfortunately, you can't get two grades (or degrees) for the same work so even if this is done in innocence, it is still classed as plagiarism.
All of the above are types of plagiarism to a greater or lesser degree and should be avoided at all cost!