A legitimate ROM site will give you the file directly. If a site asks you to download a "special installer" to get the ROM, leave immediately.

Many users upload "No-Intro" collections here. Searching for "Nintendo 64 No-Intro Collection" on Archive.org is the safest way to find an original, verified copy of Paper Mario.

The Megathread pinned at the top of the r/Roms subreddit is the gold standard for finding safe links to almost any retro game. Staying Safe Online