There are many types of OLED displays available in the market the most popular one is the Monochrome 7-pin SSD1306 0.96” OLED display which we are discussing here. This display can support both IIC and SPI communication. When you receive the module from the factory it will be in 4-wire SPI mode by default and it is the fastest of all available modes. However, you can re-solder the resistors in different positions to make it work in 3-Wire SPI and IIC protocol also.
Once you have settled on which protocol to use you should jump into the datasheet (given below) to know how to communicate with. The IC supports both 3.3V and 5V logic devices so hardware should not be a problem. If you are planning to interface with Arduino, then all the hard work is already pulled over by the Arduino community by providing you ready-made library. Make sure you have made the connections correctly and used the correct library and you are all set to go.