I firmly believe that you should try both approaches and experience yourself what works best for you.
Would you marry someone that you have never seen? Would you sign up for a job, or employ a new worker, without some practical probation? Would you buy a car without testdriving it? Would you decide on a lifelong diet without trying at least one meal? Do you try on your shoes and clothes?
Why the hell would you decide to write in a certain way without having tried the other way at least once?!?
People are different. What works fine for some of the answerers here, might not work for you. Not everyone finds the same persons attractive. Not everyone likes the same kind of food. Not everyone wants the same job. Not all clothes fit everyone equally well. To find out what fits you in writing, you have to try it on.
Both outline and no outline have their advantages and disadvantages.
Outlining gives you more control and usually results in a more tight arc of suspense and satisfying end. No outline on the other hand often feels less constucted and flows more naturally.
No outline writing will require more painful rewriting, since cleaning up the loose ends and filling the plot holes will force you to change what on the gut level feels right to you. No outline writers often have writer's block in the rewriting phase, losing the feeling for their work. Also, having to write the same thing twice is often almost impossible for "discovery writers", as they are sometimes called: writing for them is experiencing, and they have already lived this life, and living it again is simply not possible. Rewriting makes their story feel stale and wrong for them.
Outline writing carries the danger of overthinking, overplanning, and too much backstory. Outline writers sometimes get lost in research, world building, and characterization, and they will sometimes find it difficult to clearly see how much needs to be included in the story and what needs to be trimmed and deleted, or what is missing because while they know it their readers won't.
Some professionals have found, through trial and error, a combination of both approaches that works for them. Some, like Brandon Sanderson, create a rough outline of the plot, so they know the route they are taking, but leave the character development and those characters' exact actions open for discovery during the writing process.
A good procedure will depend a lot on the kind of story you want to tell. A detective story will need more planning, or else the riddles, clues and resolution won't add up. A character study like a story of a cast of characters forced together in a difficult situation will need more character planning, and might leave the development of the story open for discovery.
Beyond that, what works for you will depend on the kind of person you are, and only you can find that out.