If you want to give 1 or 2 or how many you want pokemon to have alot of friendship then your at the right place here are some things that will help you grow to max friendship with you and your pokemon
1:Battle alot with the pokemon without it losing alot of hp or the battle.
2:Walk alot of steps which will increase the pokemons happiness.
3:Catch it with a luxury pokeball.
4:Give it a soothe bell item and walk/battle with it.
5:Give it some poffins.
6:Give it a protein,carbos,iron,etc.... which will both increase its friendship and its stat.