If you do not have a passport valid through October 2024, it is now time to renew or apply for your passport. The expiration date needs to be after you get back to the US. It currently takes 6-8 weeks for standard requests and 2-3 weeks for expedited. Passports cost $130 and if you need to expedite, that is an additional $60. You can also pay an additional $20 to get expedited shipping which will speed things up even more.
Everything you need starts at this webpage https://travel.state.gov/content/travel/en/passports.html
If you are applying for a new passport, you will need to fill out the forms and bring the appropriate proof of citizenship to a passport acceptance facility which includes many post offices, town halls and some libraries. To find your nearest location look here: https://iafdb.travel.state.gov
If you just need to renew, this can be done by mail, just fill out the forms and send them in with your old passport and some new passport photos. They will send your old passport back with the new one.
All applications require a passport photo, this is a specially-sized photo that is done in duplicate. You can get these photos at any CVS with a photo counter or AAA.