When starting a new game, you need to pick a starter Pokémon, and which one you pick will affect the rest of your game in some way. Most people will just go for their favorite, and you should, but in this guide we will talk a little but about the pros and cons for each starter Pokémon, so you can decide which you want to have by your side.
Rowlet is the little bowtie-owl, and is a grass/flying Pokémon. It evolves into Dartrix at level 17, and Decidueye at level 34. Decidueye is pretty well-rounded at higher levels, and has some cool moves such as one that prevents opponents from fleeing. This makes it great for capturing new Pokémon, and a great pick for casual gamers. He is not all that good at competitive play.
Litten is a Fire Cat Pokémon that is a fire type. It evolves to Torracat at level 17, and finally Incineroar at level 34. Incineroar is a very good choice, and is the best competetive pick of all the starter Pokémons. He has a large health pool, and a good attack stat.
The final starter Pokémon is Popplio, the sea lion. He is a water type, and evolves to Bironne at level 17 and Primarina at level 34. Primarina is an overall good Pokémon that is a safe pick, but lacks the competitive high-level part in its arsenal.
All three are overall good picks for playing casually, and will do nice against the gym bosses, but if you are one of the people who are looking to beat strangers in Pokébattles over the internet, you should go for Litten.