The easiest way to import EML files into Outlook.com account is to use the Outlook desktop application since Outlook.com does not allow direct uploads of EML. One option I would recommend is to convert your EML files to PST files. Outlook can open a PST with ease and once you have this opened in desktop Outlook, your emails will sync to your Outlook.com account. Use the FixVare EML to PST Converter for the conversion step. This converter can convert several EML files into a single PST and will keep the formatting and attachments. Once converted, just open the PST in Outlook and let it sync your Outlook.com account and your imported emails will show online.