Applying for jobs online that are not real, or not what they seem, is not only a waste of time but can also be a waste of money. As a general rule, if someone is asking you to give money in any way, shape, or form so that you can work for them, they are not offering you a real job. There are exceptions, as in sites that require a fee to show you job opportunities, but research such a web site first to make sure it is on the up and up. Otherwise, anyone who asks for money up front is just going to take it from you without any type of real work coming your way.
If you are sure you have found something legitimate, applying for jobs online is much like applying for those you would seek out locally and in person. Be sure you have your resume ready and uploaded to your computer. Be sure it is free of errors and is also tuned to what you want to do. Some people want to see this and some do not. Others may just want to see what experience you have in the field through which you are applying for work. Have a list of your experiences ready if you have any. Again, be sure your list is free of any errors.
Those applying for jobs online sometimes think they are going to make fast money for doing almost nothing. Any real job that you find online that allows you to work from home is going to require effort on your part. You have to work as if you were in an office and keep in mind that no one is going to pay you well for doing nothing. What you earn will be comparable to what you put into it. You are not going make a few thousand a month for clicking on a few web site links. Be prepared to work for your money just like you would anywhere else.
Some companies in your community may accept applications and resumes online. If applying for jobs online to work outside the home, act as if you were in an office while applying. Be honest about experience and your education, as they are going to check these things. Some think applying online means an easier hiring process, but the opposite may be true. You won't have to meet someone in person as soon, but expect that the same will be required of you as if you were walking in in-person and applying for a job in your community.