I use 5.7v Laravel and 7.2.1v PHP and composer last version, but when I like to create new project these errors appeared:
Your requirements could not be resolved
The problem seems to be what the error message says - your system is missing fileinfo PHP extension. Since you're on Windows, open C:\php-7\php.ini file, search for the following line, and remove the beginning ; if exists:
;
extension=fileinfo
or in windows with IIS
extension=php_fileinfo.dll