How do I lock a pre populated field if a value is already pre-set in the URL?

We have referral program and when people click on the link we want to lock the referral box if we have pre-filled the field in the URL with a company or person. This way we are guaranteeing their commissions

For example https://scwake.com/request-a-quote/?referral=Persona

Result:

Hi Wake_info,

Thanks for reaching out to Jotform Support. I'll need a bit of time to look into this. I’ll get back to you as soon as I can.

Thanks for your patience, we appreciate it.

Hi Wake_info,

I understand that you want to lock the How did you hear about SC Wake? field that is already pre-populated when form fillers are being referred. To do that, you will need to set conditional logics using Enable/Require/Mask Field element. Let me show you how:

1. In Form Builder, click on the Settings Tab at the top, then go to Conditions Tab on the left side panel.

2. Click on the +Add Condition button and select Enable/Require/Mask Field element from the options.

3. Set similar conditions below:

Check out the screencast below to see my results:

Give it a try and let us know if you have any other questions.