There many on-going Industrial Zones set by Myanmar government and the ones with help of other countries such as Japan. However, there are many areas set by the government long time ago within the Yangon area as well.
Some are developed enough for you to set a factory, some are not. Some are only good for warehouse usage which could be very affordable. You should be very careful where to choose for your needs.
If you are not sure, we will help you find the right place for you.