This page of the guide to Halo Infinite explains whether you can save the game manually in the campaign. Additionally, you'll learn how to restart a mission and when it's worth to do so.
Halo Infinite does not allow for manual saving. Thus, you can't save the game state or use different slots for your saves.
You must rely solely on autosaves. The game displays a notification on the left side of the screen at each autosave. Fortunately, autosaves are very frequent and can occur even during bigger fights that have several stages. This means that if you die or turn off the game, you won't lose a lot of your progress.
When you pause the game, you may notice that the manual save option has been replaced with Restart Mission. This option is generally not very useful, because you won't need to restart any mission from the beginning. However, there may be some exceptions:
- a game error/bug that prevents further progress in the current mission (e.g. getting stuck in an object, a passage that won't open),
- wanting to collect some missed secret or other valuable object - in this case, restart the mission while you're still in its early stages to avoid replaying the majority of it.