From QB64.org wiki
The MKDIR statement creates a new folder (directory) at a specified path.
- MKDIR pathSpec$
- The path specification (pathSpec$) is a literal or variable STRING expression that also specifies the new folder's name.
- If no path is given the directory will become a sub-directory of the present directory where the program is currently running.
- QB64 can use both long or short path and file names with spaces when required.
- The new folder will be created without a user prompt or verification.
- If a path is specified, the path must exist or a "Path not found" error will occur. See _DIREXISTS.
- SHELL can use the DOS command "MD " or "MKDIR " + path$ + newfolder$ to do the same thing.