i had seen that notation ul and f after variables and numbers in code and do not know the exact usage.
UL stands for unsigned long. It tells the compiler to treat the number as an unsigned long, rather than an int.
F stands for float. For systems where float and double are different sizes, a literal is treated as a double. The F tells the compiler to treat it as a float, instead. On the Arduino, floats and doubles are the same, so F is not needed.