This works for all versions. This is useful on servers to hide your valuables or have a secret mine or whatever you wanna hide :)
Start with a 2x1 doorway (the wall size doesn't matter, it just has to be at least as big as this wall)
Place signs on the doorway (you can use a door or any other item you can walk through, but I like signs the best).
Place a painting so that it covers the hole.
And now you can walk through your secret passage!
This is a good request from Lara (keep em coming guys :D). I hope this was helpful!
If you have a question, or want a guide, leave a comment or send me a message and I will always answer :)