Can plural form of words be used in the scrabble? For example, table, obviously can. But can I extend it to the "tables" for example?
Any word that is found in a standard English dictionary can be used in the game of Scrabble. There are also Official Scrabble Dictionaries that can be purchased for more word options. (Rules source)
Any word found in a standard English dictionary is allowed, which includes plural words.
You can look up a word to see if it is legal here, and searching "tables" shows it is legal.