The main goal of Provisioning is to craft powerful food or drinks that enhance your stats. To successfully craft food or drinks in the Elder Scrolls Online you need to farm ingredients and recipes.
What does a Provisioner do?
A Provisioner collects Recipes and Ingredients found throughout the world to make a wide array of food and drinks. Recipes, needed to learn how to make new types of food, can be found in chests, trunks, desks, as well as from other adventurers and sometimes even from fallen enemies.
Ingredients can be obtained a number of ways, including purchasing them, searching populated areas as well as various containers, killing animals, fishing, receiving hireling deliveries, and fulfilling Provisioning Crafting Writs.
When a Provisioner finds a new recipe they can learn it by using it from their inventory. This action will add it to their recipe book. Provisioners also create known food and drinks by utilizing one of the many usable cooking fires found throughout the world.
Foods give long term boosts to health, magicka or stamina while drinks are more focused on recovery rates.
Food
Food in general is more focused at increasing resources stats such as health, magicka or stamina, like you can see in this example here. In this example we can craft a dish called "Crisp and Crunchy Pumpkin Snack Skewer" which increases our magicka and stamina by 4592 for 2 hours. 4592 is a huge boost to our stats!
Drink
Drinks are more focused to also provide you with recovery stats such as the "Witchmother's Potent Brew" here. We get 2856 magicka, 3094 health and 315 magicka recovery.
Level Requirement
Some food or drinks do have level requirements, generally speaking though the new ones usually are scaling to your level. That means you can use them from level 1 to the maximum level all the time without losing anything. For example the drink example Witchmother's Potent Brew is a drink that scales, therefore you can use it at any level.
Furnishings
This might come as a surprise to you, but at the Provisioning Fire you can also craft certain furniture. To do that you have to go to the third tab which is called "Furnishings".
Once you crafted an item you can place it in your home.