Viridian City

Viridian City is a small city located in western Kanto. It is the 2nd city players will come across in-game, however, you cannot complete the Viridian Gym until you've beat every other gym leader first.

Officer Jenny
Officer Jenny can be found to the right of the Pokemon Center. You can get these 3 quests from her:

1) Beat bug Catcher Gerald

2) Clear Route 1 of Rattata

3) Catch a Sentret

Surfing
Headbutting Trees