How would I know if I am fit for green card application?

There are two processes of petitions to apply for green card, the first petition is the 2-year green card application process, as long as you have been granted a US entry via the ​K-1 or you are married to your US-citizen petitioner is one of the basic requirements.

Another one is the 10-year ​green card application process​ in this petition You must first granted US entry via the CR-1/Spousal or Family Visa petition and must be married to, or directly related to your US-citizen petitioner and you are ready to fill up the ​green card application forms​.