The huge amount of fights in New World means that you will have to often heal your character. On this page of the guide, you will learn how to restore health. There are two methods of healing - through food and potions.
The cheapest and easiest way to heal yourself is to use Recovery Foods. This option appears at the beginning of the game. Just kill an animal (e.g. wild boar living in the first locations) and then use a Flint Skinning Knife on it. You craft this item in one of the first quest of New World. Once you obtain meat, go to the fire and cook it into Light Ration. Bonfires and other places for crafting are scattered around the game world. You can also create a bonfire in your camp.
The created item must be placed in the quick access slot so you can use it later. Light Ration is of course not the only health-restoring food. You can also find other food (e.g. bread), and, later in the game, you will get access to better rations.
The healing effect of food is spread over time. This means that eating a meal won't restore a large number of health points right away, only a few points per second or minute.
A more effective, but also more expensive healing method is using Health Potions. As opposed to eating, drinking a potion will restore health right away (the amount depends on the quality of the potion). To create potions, you will need herbs collected with a sickle. You can also buy or find them in the game world.