To set up shipping accounts for FedEx, UPS, and USPS within your Shippo account, follow these steps. Please note that while I'm providing general steps, the exact process might slightly vary and you should refer to the official Shippo documentation or their support for the most accurate and up-to-date information.

1. FedEx

   • Log in to your Shippo account.
   • Go to settings, then click on 'Carriers & Fulfillment'.
   • Click on 'Add Carrier Account'.
   • Select FedEx from the list.
   • You'll need to enter your FedEx account number, Meter Number, and other required information. Click 'Submit' when you're finished.

2. UPS

   • Log in to your Shippo account.
   • Go to settings, then click on 'Carriers & Fulfillment'.
   • Click on 'Add Carrier Account'.
   • Select UPS from the list.
   • You'll need to enter your UPS account number and other required information. Click 'Submit' when you're finished.

3. USPS

   • For USPS, Shippo provides discounted USPS rates and the account is automatically set up for you when you create a Shippo account. You don't need to manually add a USPS account unless you have a specific USPS account you wish to use.
   • If you do have a specific USPS account, follow similar steps as above to add it to your Shippo account.

Remember, you must have an existing account with FedEx and UPS to add them to your Shippo account.

As the search results don't provide specific link or source for step-by-step instructions, I recommend reaching out to Shippo support or checking the Shippo help center for more detailed information.