I go to a high school and I'm a junior, I was doing well but thisyear was disastrouos for me so I almost failed, however, I had to travel to the usa after school ended and honestly I was thinking about it way too much which led me to forgetting about school and failing my final term thus failing my school year, however, my school gave me something that proves that I had succeeded and canceled my final term,and I am willing to apply to a school here in the US, so my question is woukd they accept me here in a public school? Or would they ask me to repeat my school year, or would they just not accept me... PLEASE HELP

First off... its not that simple. Do you have a VISA to be here... Do your parents have a VISA to live and work here too?

Besides the fact it takes years to get, not days... weeks or even months.

After you have proof as Smoothy said, you will need to apply at a public school district office. They may test your skills in various areas, such as Math and Language. Depending on what country you are from, they may test your English. They will also need a copy of your transcripts to show what classes you've taken and what grades you earned.