Sign In to your Google Account.
Click on Create API Key.
Enter this key on the website Convert PDF Statement.
This is a free API Key. For free API key, Google will use your data to train their models.
Also, gemini free plan will not be available in some countries, so you will have to buy their Pay-as-you-go plan. The paid plan is also very cheap. In the paid plan, your data will not be used by google.