For some applications, such as through airlineapps, you need to have your SSN to create a profile. As you don’t have the GC yet I assume you don’t have your SSN either. That means you are not able to apply at Delta or United for example. All other applications ask for the minimum requirements of having an ATP and the right to work and live in the US. If you still have one year until you’re available, I recommend starting an online degree asap. You will get some credits for an FAA ATP once you have it. As others have said, I doesn’t hurt to fill out an application where it lets you. But don’t expect any response until you at least have the minimum requirements as the GC and an ATP, preferably with a degree of course.