When you are creating a feed for your preferred merchant with the Product Feed Manager, you will see that the required attributes are already included in the feed.
However, you will find only the required attributes in the feed template. And there are other recommended/ optional attributes that you may need to add to your feed.
In this case, you can easily add those recommended/ optional attributes with the Product Feed Manager plugin.
Let me show you how you can add a custom attribute to your feed.
1. At first create a new feed, select a merchant or open your existing feed.

2. Scroll down to the Feed Configuration section. Here you will see all the attributes that are included in this feed.
On the bottom, you will find an option, Add New Attribute.
Now, to add a new attribute, click on the Add New Custom Attribute button.

3. Once you click on the Add New Attribute button, a new attribute will be added to your feed.

Here, select a new attribute, select attribute type, and set a value to this.
You can keep the Output Sanitization as the same it is, or you can change Sanitization as per your need.

Your custom attribute is ready now.
4. Now, go back to the top and click on the Publish/ Update button to Publish or Update your feed.

And now if you check your feed you will see that this new attribute is added to your feed.
To remove your existing attribute, you can click on the delete option next to the attribute from the feed configuration and that attribute will be removed from the feed.

That’s it, your attribute will be deleted from your feed.