BackOffice>>Preferences>>Contact
When you first installed Prestshop, you would have supplied a shop name and default shop e-mail address during set-up.
With the contact section, you can update this information and complete the additional fields including;
Registration
Shop Address
Post/Zip Code
City
State
Country
Phone
Fax
Its all quite straighforward, complete the fileds and click "Save" Thats really all there is to it.