Actually, there are many different types of conclusions for essays. However, there is only one rule for writing: conclusion should be the summary of the entire paper and yet it should not present new information. The type of conclusion depends on the specifics of your assignment. For example, there are types of conclusions for expository essays, persuasive essays, etc. Similarly, there are different rules for writing introduction.
My advice is to ask professional essay writers about this. If you need help with writing your essay, you can always turn to reliable essay writing service online and get assistance with any assignment.