Rejected your question because the answer can easily be found on this site at the page linked below.
https://pokemondb.net/type
"Another advantage you can gain is Same Type Attack Bonus (STAB). As the name implies, this increases the power of the move if the attacking Pokémon has the same type as the move used (for example a Fire-type Pokémon using a Fire-type move). In this case the damage is 1.5 times normal."
