Hello Lesley,
To have an automatic SMS Text Message sent out based on a Form submission, you can create a CRM Workflow that will run on the creation of Posted Fields. It will check to see if the value in a field ( like a mobile number field) is a certain value or contains data, then will create a Bulk Text Message record to send to the person who submitted the Form. Once the Workflow is activated, it will send an automatic text depending on a Posted Field submission.
These articles here and here show another way to send a text message automatically using CRM Workflows.
If you send your text messages via Twilio and anyone replies, those replies will come back into ClickDimensions as SMS Replies. Those replies will be stored within your CRM as Activities. You could then create a CRM Workflow that runs on the creation of an Activity and will create a Bulk Text Message which could contain your loan application link.