Hey! "Awhile" is an adverb. "A while" is a noun phrase. I can say, "She will be sleeping awhile longer." I can also say, "She will be sleeping for a while." I hope this helps! If you need any more help, I am a professional TEFL-certified English teacher and a native speaker. Feel free to look at my teacher profile.

I think 'awhile' is less common and more poetic. Also the equivalent phrase is 'for a while' Can you stay awhile to keep me company? Can you stay for a while to keep me company?

A while is more common I guess