Note: You can update the title, bullets, and description in two ways. One would be through each listing within the Manage Inventory page and the second method would be using flat files.
MANUAL UPDATE
1. In Seller Central, go to the Inventory then, click "Manage All Inventory" to view the listing you want to modify.

2. The image below is a sample where you can see all of the listings on Amazon, both active and inactive. Just look for the item that you need to edit and click the "Edit" button on the left.

3. Update the General Info
You should reach the general information page. This is where you can update the Title, Bullets Description, and all other information.
The title can be found under the Product Details Tab while Bullets and Description can be found under the Product Description Tab

4. When you're done updating all the attributes, click on the "Save and Finish" button.

5. Once everything is all set, you should see it reflect on the product information page. Be advised that other categories will have different information, so just adjust accordingly.
FLAT FILES
1. Before you can upload a flat file, you have to download it first. You can use the Category Listings Report or download it from Download an Inventory File.
2. Once you’ve logged in to your Amazon Seller Central account, click on ‘Add Products via Upload.

3. When you are on the 'Add a Products via Upload' page, navigate to the 'Download Spreadsheet' option and select 'Get Product Template.'

4. A pop-up page will appear where you need to specify the appropriate marketplace template. Ensure that you obtain the template corresponding to the marketplace you wish to update your listing on.

5. Now you’ve got to find the inventory file that’s relevant to the product, there are lots of different flat files depending on what category the product falls in. If, for example, the category is baby products, type that into the search field and click on ‘Search’:
NOTE: Bear in mind you’ve got to select the correct category from the search by clicking on Select:

6. In this case, you have to scroll down the page you will see this selected, then proceed to click the ‘Generate Template’ button:

7. It then creates an Excel flat file that you can download.

Rule of thumb! If you are only told to update a certain attribute, only fill in the SKU, the attribute that you need to change, the fulfillment center, and only use a partial update.
In the sample below, we are only updating the title of a product which is an FBA listing in Partial Update.


However, if you are going to do a Full Update, it is recommended to download the flat file through the Category Listings Report and double-check each piece of information before proceeding with the upload. Unlike with the Partial Update, it is important that all required columns are filled in with the information.
For Full Update
1. Go to Inventory > Inventory Reports and Download the Category Listings Report

2. Once Category Listing Report is downloaded, open the downloaded file then go to the “Review” section and click “Unprotect sheet”. Turn on the filter and locate the listing that you are going to update (SKU) by searching it through the Seller SKU column.
Note: Make sure not to include other listings that are not part of your task

3. Double-check each piece of information before proceeding with the upload.
4. Once your file is complete, save it and upload it to Amazon, by clicking on ‘Upload your spreadsheet.' You will then see the following screen:
5. Wait until the inventory file is processed +15 mins and make sure it is uploaded successfully and keep the BATCH ID