In Roblox Rivals, you can usually turn off autofire by opening Settings , going to the game/controller controls area, then finding Aim Assist or Auto Shoot and setting it to Disable. A recent walkthrough also says you can re-enable it later by switching the same option back to Custom or turning Auto Shoot on again.

Steps

  1. Open the in-game Settings menu.
  2. Go to the controls/game section.
  3. Find Aim Assist or Auto Shoot.
  4. Select Disable.
  5. Save the setting and test it in a match.

Extra note

If the option does not stay off, some players report that rejoining, checking mode-specific presets, or resetting control settings can help.

TL;DR: Settings → controls/game section → Aim Assist/Auto Shoot → Disable.