The item satchel worn by Arthur has unfortunately a very limited capacity by default and as a result it is easy to fill it up completely. On this page we suggest how to solve this problem, i.e. how to increase the capacity of the satchel (item bag) in RDR2.
The only way to increase inventory capacity is to produce a new larger satchel. You have to contact Pearson at the Dutch gang headquarters and hold down the crafting button.
In order to make new bags you need Leather Working Tools - the way to get them is described on the page How to get the Leather Working Tools for crafting? in our guide.
That's not all, because each of the offered bags has different requirements before it can be crafted. These requirements can be related to other upgrade projects of the Dutch camp (e.g. improving the medical car) and acquisition of craftsmanship components, which can include such items like perfect quality pelts of wild animals.
The satchels offered by Pearson differ in applications - they can only increase the maximum amount of transferred items, for example they can only store a limited amount of medicines, food or jewels. Choose the satchel that suits you best. The last bag offered (Legend of the East Satchel) increases the capacity limit of the whole inventory. However, you can buy it only after you have produced all the previous bags from the list.
Additional note - Until you get better item bags, try to consume, sell or give away all the items that have reached the allowed inventory limit on an ongoing basis. This will allow you to free up space for more treasures of this kind, which you will be able to pick up when you find them in the game world.