There’s two main ways to save your game in Lords of the Fallen, each requiring you interact with red crystals scattered around the map. If you run into one, here’s how to save your game, and which way you should do it.
When at one of these crystals, you have two options. The first is to save your game, lose your experience modifier, and refill your health and potions. The longer you go without saving this way, the more XP you save up, and the more experience you will receive from defeating various enemies. This bonus is lost upon saving this way. To do this, hit Y or Triangle at a crystal.
To save without losing your experience modifier, hold down the left stick button (or left shift key on PC) while you press Y/Triangle. This will keep your XP saved up, but will not regenerate your health or potion supply.
After saving either way, you will respawn after death, with all your items, at the crystal.
As for autosaving, Lords of the Fallen will autosave automatically at certain events, like before a boss battle or upon entering a new, important location.