It can always be useful to be able to go back to the job posting, especially if you've been invited for an interview and want to prepare!
If you applied through an account
If you applied to the job through your account, you can log in and both view and download the vacancy from the list of job applications.
From "Applications" in the main menu, you have a list of all your initiated/commenced and applied jobs. By clicking on the document icon furthest to the left, you can see the vacancy for the position you applied for, and if you want to view the application you submitted you can use the magnifying glass icon on the right!
If you applied without an account
If you didn't apply for the job through an account, unfortunately, the vacancy and your application isn't saved in any place where you can access them yourself. If the application deadline hasn't passed yet, the job posting will still be available on platforms like Platsbanken or the employer's website. However, if that date has passed, you'll need to contact the employer directly to get a copy of the job posting and your application.