Hi,
Consider some election held place in your city and a exit poll was conducted to predict which party is going to win. Since, prediction in exit poll was made on the basis of public opinion and previous knowledge, they don't know who voted for whom, that is making prediction in exit poll comes under inferential statistics not descriptive statistics.
Now, consider actual result was declared, since they declared result by collecting all the data about votes and then by summarizing it by using measure of central tendency(mode) and describing or summarizing the data comes under descriptive statistics. Hence, declaration of actual result is descriptive statistics not inferential statistics.