The transition words used in order to indicate a conclusion are finally and therefore.
Transitions are phrases or words used to connect one idea to the following.
In order to sum up the idea or opinion pertaining to a topic you have addressed and developed throught an essay or writing, some transition words you can employ are: in conlcusion, consequentely, finnaly, therefore. in summary, in short, to summarize, on the whole, hence, and the like.