Please help! Teacher 8. I-864 question

Hi teacher 8,

i got got the approval of my I-130 and my PD is current. I am working in U.S. under a L-1 visa right now and would like to submit a I-485 to adjust my status to PR. Do I need to fill out I-864? Can I be my own sponsor/ support myself using my income in U.S. ? What are the forms I need to fulfill if so?

thank you in advance!