Time Signature

The time signature (also known as meter signature ^[1], metre signature ^[2], or measure signature ^[3]) is a notation convention used in Western musical notation to specify how many beats (pulses) are contained in each measure (bar), and which note value is equivalent to a beat.

Typically songs are in 4/4 time signature but other common time signatures include 3/4, 6/8, and 2/2. There are others beyond those mentioned but if you are not as familiar with time signature these other meters are not important.

Learn more: https://en.wikipedia.org/wiki/Time_signature