Tables have rows and columns, forming cells, similar to the spreadsheets you might be familiar with from using an Office Program.
They are very useful for displaying tabular data. Unfortunately, when you have to plan a website so that it can be used effectively on a mobile device as well as a large monitor, tables cannot be very wide or the formatting will be really messed up.
Here is a typical kind of table we can use on our websites:
We also use a table on this website to display the common colors available.