The programmatic workflow for this would be the same as when using ArcGIS Desktop. You'll want to 1) Convert the text file to an XY Event Layer and 2) export the Event Layer to a valid feature class format. The hardest part will be part one, as such I've written a quick example of how I'm able to accomplish this with a text file.
The below code will show you how to create the XY event layer and get a reference to IFeatureClass. After doing this you'll want to decide on if you want to use pure ArcObjects or the Geoprocessing framework to export the feature class to your needed format. For example, you could use IFeatureDataConvertor or you use use Geoprocessing tools like FeatureClassToFeatureClass_conversion or CopyFeatures_management. I have pasted links that discuss this workflows below the code.