First, see this article to learn how to get your FedEx credentials.
Here is how to setup FedEX shipping method
- Go to Preferences and click Shipping Method
- Click USPS or click Edit under Actions
- Put in a Label which will be shown to your customers
- Click the check box beside Active to make it active
- Enter the Account number and Meter Number from your FedEx credentials
- Select Packaging Type
- Select the Shipping methods offered for both Domestic and International
- Select the State where it is shipping from
- Enter the Authentication key and Password from your FedEx Credentials