This guide will let you know how to increase your inventory size in Icarus. You have to follow the simple steps in this guide to do so.
First, you will have to make a backpack, and you need a textile bench to make it. Open your tech tree, and go to the Tier 2 tab, as shown in the image below. You can unlock tier 2 after reaching level 15.
To make the textile bench, you will need to craft the crafting bench, and then, with the help of a textile bench, you can craft the leather backpack. This backpack will provide you with extra space in your inventory. After making the backpack, you need to place it in your inventory display slot.
Now you need to go to the talents tab and buy Mobile Stockpile, which will decrease the carry weight of wood, stones and ores by 20 percent, which will help you while mining.