Just as with any large corporation, or almost any employer, just go on the website of the airline and apply. Being able to use your common sense and resources to figure this out would be the minimum requirement to apply for any job.
If you need a job immediately, this is probably not the best route: airlines hire rarely and only periodically and a very small percentage of the applicants are even called in for an interview.
You need experience in customer service. If the airline is not currently hiring for flight attendants, they may be hiring for reservations, ticketing agents, ramp workers or gate agents. All of those would be a good way to start and then you could transfer internally to the FA position.
A very good website with lots of information about the career is:
They also list which airlines are currently hiring.
About the job:
Most airlines require you to be at least 18, but the most common minimum age is 21.
There is much more to the position than smiling and being attractive.
All cabin crew have extensive training in emergency procedures, first aid, security and safety.
Don't take courses on your own; this will not give you any advantage. Any airline that hires you will put you through extensive training.
To make you competitive for an airline job, you must have some good customer service background.
The ideal candidate will be well groomed, poised and friendly.
You also must not have multiple piercings (usually only one per ear lobe), and no visible tattoos, meaning nothing above the shoulders, below the elbows or below the knees.
Height 5’2” to 6’2” and weight in proportion to height.
You must be able to show that you are gracious and handle pressure well, that you are a team player and a good decision maker.
If the airline likes your resume, you will be invited to an information session, then to a group interview, and next to a one on one interview.
When the airline is ready to offer you a job, you will be asked to provide fingerprints and your passport, a 10 year background check will be conducted, and you will be given a physical assessment and drug test.
If all that is good, you will be scheduled for initial training which last 4-6 weeks.
Be prepared to relocate to whichever base you are assigned to, and to be on reserve for one year to several years.
This means you will be on call and may have to show up in uniform with luggage at the airport within 2 hours ready to fly on a multi-day trip
Get ready to fly!!