Click on Profile and select account settings from the dropdown menu.
You could see Customer Portal Tab, click on it..
Now Click on Add button from Move In Terms & Condition url option.
In "Display Document Text" you can enter the text you wish to show as link name, It can be in any language. It "Display Document Path" Enter the url of Terms & Conditions.
Now click on save button.
Note: The Terms and Conditions will be displayed in all payment page under the credit card payment type. Also this will be displayed in customer portal rent now page.