depends on the platform, OO the tendency is towards UML - use cases, collaboration and sequence diagrams etc. In a procedural world it may be Jackson Structure diagrams.
Ultimately it will depend on personal prefernce and the standards applied at the installation where you work.
Pseudo code can be helpful for solving programming problems at a very low level but can be used whenever you wish - it is really up to you.
It is not a fixed syntax, nor recognised with standards at some national level - the whole point is that it is just a very informal way of documenting/designing code logic that despite being low level, still isolates the program from the specific technical implementation of the target language.