move all files in a folder to another?

A slightly verbose solution:

// Get array of all source files
$files = scandir("source");
// Identify directories
$source = "source/";
$destination = "destination/";
// Cycle through all source files
foreach ($files as $file) {
  if (in_array($file, array(".",".."))) continue;
  // If we copied this successfully, mark it for deletion
  if (copy($source.$file, $destination.$file)) {
    $delete[] = $source.$file;
  }
}
// Delete all successfully-copied files
foreach ($delete as $file) {
  unlink($file);
}

An alternate using rename() and with some error checking:

$srcDir = 'dir1';
$destDir = 'dir2';

if (file_exists($destDir)) {
  if (is_dir($destDir)) {
    if (is_writable($destDir)) {
      if ($handle = opendir($srcDir)) {
        while (false !== ($file = readdir($handle))) {
          if (is_file($srcDir . '/' . $file)) {
            rename($srcDir . '/' . $file, $destDir . '/' . $file);
          }
        }
        closedir($handle);
      } else {
        echo "$srcDir could not be opened.\n";
      }
    } else {
      echo "$destDir is not writable!\n";
    }
  } else {
    echo "$destDir is not a directory!\n";
  }
} else {
  echo "$destDir does not exist\n";
}

Move or copy the way I use it

function copyfiles($source_folder, $target_folder, $move=false) {
    $source_folder=trim($source_folder, '/').'/';
    $target_folder=trim($target_folder, '/').'/';
    $files = scandir($source_folder);
    foreach($files as $file) {
        if($file != '.' && $file != '..') {
            if ($move) {
                rename($source_folder.$file, $target_folder.$file);
            } else {
                copy($source_folder.$file, $target_folder.$file);
            }
        }
    }   
}

function movefiles($source_folder, $target_folder) {
    copyfiles($source_folder, $target_folder, $move=true);
}

try this: rename('path/*', 'newpath/');

I do not see a point in having an asterisk in the destination

If the target directory doesn't exist, you'll need to create it first:

mkdir('newpath');
rename('path/*', 'newpath/');

i move all my .json files from root folder to json folder with this

foreach (glob("*.json") as $filename) {
    rename($filename,"json/".$filename);
}

pd: someone 2020?