Symbol which consists of two apostrophies used to indicate the word above must be repeated?

The symbol you are referring to is called a "ditto mark" or "ditto." It consists of two apostrophes (or sometimes a single curved mark) and is used in writing to indicate that the Word or phrase above it must be repeated. It is commonly seen in lists or tables to avoid redundancy. For example, if "Apple" is written above the ditto marks, it signifies that "Apple" is to be repeated for the items below.