“Walk” is by far the most common and most general of these words. Examples: “I walked five miles today.” “After the car crash, he no longer is able to walk.” “My car broke down so I had to walk home.”
“Stroll” is used specifically to refer to slow, leisurely walking. You would not use “stroll” in any of the examples above. But, you might say: “My wife and I took a stroll along the beach today. The weather was beautiful.” It is a common word, but much less general and less frequently used than “walk”.
“Promenade” is almost never used as a verb, at least in the US. Sometimes you hear it as a noun — with the last syllable rhyming with “rod” to make it sound French — to refer in a fancy way to a place to go walking. Example: “Our hotel has a beautiful tree-lined promenade from which guests can see the ocean and beautiful sunsets.”