Have ready:
Desired company name (plus a backup or two)
Entity type and state you want it to be registered in
Owner / manager / director names and addresses
Information for who will be the responsible party for tax purposes
A brief description of your business activity
Contact email and phone number
Payment method
Some states may need extra details (like professional licenses for PLLCs).
If you want us to apply for the EIN for your business, we need either a SSN for US residents or a passport for non-US residents.