How exactly do Helmets work in Apex Legend

Apex Coins can be purchased with real-world money, or earned as part of a purchased Battle Pass. They can be used to purchase cosmetics from the Featured section of the Store, purchase Apex Packs containing semi-random cosmetics and sometimes Crafting Materials, or unlock new Legends.

Legend Tokens can only be earned by leveling up (or refilling your XP bar at max level). They can be used to unlock new Legends, or purchase cosmetics in the Exclusive section of the the Store.

Crafting Metals are randomly included in some Apex Packs. 45 Apex Packs can by earned by reaching certain player levels, or they can be purchased with Apex Coins, or they can be earned as seasonal and Battle Pass rewards. Apex Coins can be used to directly purchase any generally-available (not exclusive or seasonal) cosmetic item in the game from the Armory and Legends screens.

It is currently 500, up from the original cap of 100:

What do I get when I increase my Player Level? What is the maximum Player Level?

Players can increase their Player Level by earning XP from playing matches. Each time a player levels up, they will earn rewards like an Apex Pack, Legend Tokens, or both.

Starting December 3, player Level caps at 500. After reaching Level 500, players can earn additional Legend Tokens by gaining enough XP during matches.

― Apex Legends FAQ