Adding fragrance to your soy candle wax depends on what kind of wax you are using and what brand. Usually with 100% soy wax you want to melt your candle wax to 185 degrees and then add your fragrance oil at 175-185. This ensures that the oil mixes well with the wax. If you add it too cool, it will not incorporate with the wax very well. With soy votive wax blends, you want to melt your wax to 195-200 degrees and then let it cool down to 180-185 to add your fragrance oil.
Different wax manufacturers may have different instructions, so follow those first if they differ from what I’ve told you. If that doesn’t work well, then try the above temps to add your fragrance oil. There are many different blends of soy wax so they also may have different temperatures to heat them up to so make sure to follow those instructions. Heating your soy wax too hot can cause it to discolor which is not good if you are using no dye.
Questions? Feel free to ask!