Disk Utility Erase "Scheme" Options

It probably refers to the partition map to use in your flash drive. If you want to use the flash drive only with Macs, use GUID Partition Map by default, but if you want to use it with other PCs (or as a boot drive for old PCs), choose Master Boot Record. Apple Partition Map is only for PowerPC-based Macs.

Thank you.

Wouldn't it be great if this information was available in the Disk Utility help menu? Still, this happens to me with many Apple app help menus. I guess the Apple help menu is the reason Goole exists.

You're welcome!