Getting a few EML files into Outlook is usually not the difficult part. The real headache comes when there are hundreds of messages, separate folders, attachments or important dates and headers that need to stay intact during the move.
If you have only a handful of EML files, simple drag and drop may be enough. When you have a larger collection, converting the EML files into an Outlook compatible PST is a more organized approach. Softaken EML to PST Converter can handle EML and EMLX files in bulk and is designed to retain folder hierarchy, attachments, SMTP details, dates, HTML formatting and inline images during export.
I would first preview a few messages and check attachments before doing the complete conversion. Then save the data into a new PST and open that PST through Outlook. This avoids having to manually import every EML file one at a time.