Strength, Perception, Endurance, Charisma, Intelligence, Agility and Luck. These baselines are also known as attributes. Their values can vary from 1 (depressingly inadequate) to 15 (God-like). Each of the attributes in its own way changes you and allows you to use a certain number of Fallout 76 cards perks.
When performing tasks, exploring the world and in battles with enemies, you will receive experience points. When the points accumulate in sufficient quantities, your level will increase.
Having obtained a new level, you can improve one of the SPECIAL attributes and select a new perk (from the proposed set). Open your Pip-Boy and enter the upgrade menu. Select the SPECIAL attribute you want to improve, then take a new perk.
Perks are special skills that can affect almost everything: from damage in combat and support from teammates to breaking locks and terminals.