Can someone please let me know which model to chose (from the US) for someone who would like to use iPhone 6+ in the United Arab Emirates (UAE) for carrier Etisalat or DU. Where can I buy the phone? Is there an international version, can I buy a normal version? Thanks!
Your best option is to buy a factory unlocked unit
You can purchase it from a large online retailer such as amazon or even the online apple store and have it shipped to you. If you have someone visiting the USA for you or you are going yourself, go to the apple store, or a brick-and-mortar retailer such as Best Buy.
Make sure that the phone you're buying is the same technology that your carrier uses. That is, if they use CDMA technology then make sure you buy a CDMA phone and if they use GSM make sure you buy a GSM. In simpler terms, if you use a SIM card, buy GSM. CDMA might have additional configuration complications.