There are some great free tools to create HTML tables that you can then embed into your site. Here's one:
To use it, first set the table size (columns and rows) at the top, using the Table drop down:
Once that's done, click in the first cell and start typing! You can use your tab key to move from one cell to the next.
You can use the other features (bold, text alignment, size etc) also, if you'd like. When you're done, you can click Generate, then copy the code to your clipboard (right above the field with all the code in it):
The preview button is handy to see what your table will look like.
Under "Extra options" you can even choose to make the table responsive, for visitors on mobile devices.
Have fun with your tables! :)