Step 1. Open Facebook and log into your facebook account.
Step 2. Open Facebook Account Center and click Download or transfer information.

Step 1. Click Specific types of information.
Step 2. Scroll down to find and click Messages. Then click Next.
Step 3. Choose Download to device. Then click Next.
Step 4. Click Date range and change ‘Last year’ to the appropriate timeframe for the messages you need to export and click Save.
    Click Format. Change ‘HTML’ to JSON and click Save.
    Click Media quality. Change to the appropriate value you need.
    Click Create files.
Step 5. It will take several minutes for Facebook to process your request. When your data is ready, Facebook will send you a notification via both email and the Facebook website/app.

When your download is ready, Go to Facebook Account Center, you will see an entry labeled Available Downloads.
Click the Download button to download the .zip file to your computer. If there are multiple zip files, make sure to download all of them.
Please enter your facebook password.

Note: All of your downloaded messages are stored locally on your computer, ensuring their privacy. Only you have access to them.