Thanks to Michał Roszka’s comment I can write how to pronounce my nickname “Hrw” and name of my company “HaeRWu” (both sounds the same):
A phonetic transcription in the International Phonetic Alphabet should help all non-Polish-speakers or at least English-speakers to pronounce “HaeRWu” correctly. It is: /hʌ eə vʊ/ or /xa ɛə vuː/.
Or just use English pronunciation of letters.