It is a good idea to keep your character's gear upgraded to match your level - upgrading increases the item's stats, which will make it more effective. A weapon upgraded to your level, for example, will deal more damage.
However, you cannot make those improvements on your own. To upgrade your gear, you need to visit a blacksmith in-game. Talking to any blacksmith in the world will bring up an Upgrade option.
You can then select the item you would like to upgrade. Each item can be upgraded several times and the effects will stack. To further improve an item, you can also add an engraving.
Although you need the blacksmiths' help to upgrade your gear, you can craft arrows yourself.
If you have any questions, feel free to contact us!