We want to solve the inequality
Recall that the absolute value function, that is on the left, measures the distance between the input (x) and number 0. So, if we translate this inequality to words, it means "all numbers x such that the distance between the number and 0 is less than 3".
One way to figure out the answer is graphically. If we draw a number line and we identify 0 and the numbers that are at distance 3 (that is 3 and -3) we would get
So, we highlight the numbers that are right after -3 and before 3, as these numbers would have a distance of less than 3. So we get
That is x>-3 and x<3