The bag can hold more items, according to the weight you can carry. 

■ How to Check Your Bag Weight

 1. Select Level on the top left to activate character stats.

 2. Tap the magnifying glass at the bottom of Character Stats and check the Stat settings.

 3. Check your Max Carry Weight in the Health section.

You can increase your Max Carry Weight through collections, mount stats, and item options. 

You can also temporarily increase it with the Carry Limit Increase Scroll available from the General Merchant.