Electrical sockets (outlets) in Burma (Myanmar) usually supply electricity at between 220 and 240 volts AC. If you're plugging in an appliance that was built for 220-240 volt electrical input, or an appliance that is compatible with multiple voltages, then an adapter is all you need.
For the most part, electrical sockets (outlets) in Burma (Myanmar) are one of the two European standard electrical socket types: The "Type C" Europlug and the "Type E" and Type F" Schuko. Also reported to be in use is the "Type D" Indian socket. If your appliance's plug doesn't match the shape of these sockets, you will need a travel plug adapter in order to plug in. Travel plug adapters simply change the shape of your appliance's plug to match whatever type of socket you need to plug into. If it's crucial to be able to plug in no matter what, bring an adapter for all three types.
The electricity supply in Myanmar is unreliable; black-outs can occur regularly, particularly in rural areas. It is therefore advisable to have a torch for the occasional drops into darkness, particularly if you are staying in budget accommodation.