Quick correction: "I am studying English, and in my job I sometimes answer(?) calls in English. The caller asks me for help and I don't know how to ask what the purpose of their call is. Please help me." Well, here are some useful (and professional) phrases: "How may I help you?" "May I ask what you are calling in regards to?" "May I ask who you are looking for?" "Please hold a moment. I'll find someone who can assist you." If you want to ask the caller's name, use: "Who may I ask is calling?" "To who am I speaking?" Don't be afraid of the longer phrases - please try them. Of course native speakers will understand shorter sentences and "hi/hello", but you won't sound professional.

Hola Angie y muy Buenos días , apenas hablo español y aún estoy aprendiendo , pero creo que te puedo ayudar. Hay que decir: "Hi , How can I help you?" o tambien se puede decir , "Hello , what can I do for you today?" Tradicido es "Como , te puedo ayudar?" y "Que puedo hacer para usted?" Ojala te ayudé , nos vemos