If you are an administrator for your church profile, you can edit/update all information by logging in to FaithStreet and clicking on the appropriate links in your Church Dashboard.
Account: Edit basic contact and address information
Description: Edit details about your church, service times, etc.
Pastor: Edit the church leader description and photo
Events: Add events for your church (past events will not show up publicly)
Photos: Add or remove photos
When you are finished, don't forget to click on the 'Save Your Changes' button at the bottom of the page.
If you want to change or become an admin for your church profile, please see this question.