Quality Assurance for Features

The SM could in theory create PBIs if the PO has delegated that responsibility to the SM; however, the SM may be too busy to do this as they not only server the PO, but the Developers and organisation too. 

Quality should be part of the Definition of Done (DoD) and should never decrease during the sprint.  The Scrum Team should agree on the DoD. 

Now I have some tasks in my company to describe Features. But I am wondering if this is really a task for a Scrum Master or for the Product Owner.

Let's take a step back. What is it about this work that makes it appropriate for Scrum at all?

Based on this post and another post you have done in the forum, I'm going to start the response to this by saying you need to read and understand the Scrum Guide. That should be your first step towards becoming a Scrum Master.  Mastery of the meaning of the guide and not the actual words is what you want to achieve. 

Now I have some tasks in my company to describe Features. But I am wondering if this is really a task for a Scrum Master or for the Product Owner.

Here is the link to the Scrum Guides section that describes the Product Owner and the Scrum Master is the next section. https://scrumguides.org/scrum-guide.html#product-owner   My understanding based on those sections is that describing a new feature is the responsibility of the Product Owner.  That individual could delegate that work to anyone else but ultimately they retain the responsibility. 

I was asking myself if you have experience with Quality Assurance for Features

I have many years with this as a Quality Assurance representative that overlaps with my Scrum and agile experience. But I am not sure with what you are asking us for help.  There are a LOT of aspects of Quality Assurance but the fact you are asking about it here in a Scrum Forum after talking about getting "some tasks ... to describe Features" is confusing me.  Can you clarify this so I can give you a better opinion? 

Hello,

Let me explain in a simple term.

In scrum, there are separate roles and responsibilities. 

Scrum Master can teach to PO about

- how to do verticle slicing of features ( so it can be delivered in a sprint or few sprints) , 

- how to prioritize features using diff. models like KANO, MoSCoW etc.

- How to write user stories in the best format. 

- How to write acceptance criteria etc.

So, SM is a scrum expert & PO is a product domain expert. he is the voice of the customer. He knows very well how t describe features. But if you will give some tasks to describe features to SM then he may skip some important information in the description. 

So, in our organization also conflicts occur for accountability, roles and responsibility and we are managing collaboratively. But in your scenario, we can't mix up PO and SM tasks.