From QB64 Wiki
The MKDIR statement creates a new directory at a specified path.
- MKDIR pathspec$
- The path specification 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.
- Qbasic folder names are limited to 8 characters(no spaces) and filenames use the 8.3 naming convention.
- 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.
- SHELL can use the DOS command "MD " or "MKDIR " + path$ + newfolder$ to do the same thing.