...
There are some CMS page that admin can edit such as Privacy Page, Membership Information Page, Store Policy page, etc.
1. Edit text
On the admin sidebar, go to Content > Pages.
...
After finish, click on Save button to save the change.
2. Set content to center align
In the Content section, click on Show / Hide Editor button to show the content in the form of code.
To set the content to center align, put <div class="container"> and </div> at the beginning and the end of the content.
Click Save to save the change.
...