You can usually change your hitnumber in Roblox Rivals from the game settings or a related display/customization menu, not through any exploit or external script. A recent Rivals settings guide says the game’s settings area includes controls for things like crosshair, FOV, audio, and other gameplay options, which is where you’d check for hitnumber-style UI tweaks or damage indicators.

What to try

  1. Open Rivals and go to the settings gear in the main hub or in-game menu.
  1. Look through game settings , video settings , and UI/crosshair options for anything labeled hit numbers, damage numbers, damage indicators, or combat feedback.
  1. Reset settings if something was changed and the option seems missing.
  1. If you were referring to a phone number in Roblox itself, that is changed from Roblox Account Info under Settings , where Roblox has an Update Phone option.

Important note

A few search results about “changing hitboxes” or “changing stats” in Rivals were tied to cheating or script-based claims, which I can’t help with. The safe and legitimate path is to use the in-game settings and official Roblox account settings only.

What the evidence shows

One Rivals guide explicitly says the settings menu is where you can adjust controls, FOV, crosshair, and related gameplay options, so that is the first place to look for any “hitnumber” setting. Another Rivals video shows a different customization option under General settings , which supports the idea that Rivals hides some player preferences inside the game menus rather than on a separate screen.

TL;DR: check Rivals’ settings menu first; if you meant your Roblox account phone number, update it in Roblox account settings.