Just as you can create custom fields, you can make them required as well.
Access the Setup Menu, located at the top right of Rethink. Select Setup, and choose Object Manager from the navigation bar, then find the Object you're wanting to add the required field to.
In this case, we're adding a required field to the Property object, so we'll select Property.
Select Page Layouts and choose which property record type you would like to add the required field to.
Once you are on the page layout, you will see all the fields associated with this property, and for this example, we will take a look at the Office page layout.
Hover over the field you would like to make required and click on the wrench.
Select the Required check box in the Field Properties pop up, then select OK.
You will then see the field is * required. Be sure to click Save in the top left-hand corner.
To make sure your updates have been saved, go back to the front end of Rethink and create a new property. You'll see that Address is now a required field. 
*Please note, you will need to follow all the steps above to add required fields to different record types within an object.
Please reach out to Product Support (rethinkcrm@buildout.com) if you have any questions about editing fields.
