Hi @rkadey ,
I am not aware of OOB way inbuilt in PowerApps Portal, especially for the basic form. But you can achieve it with jquery or JavaScript
Once you add your disability field in the basic form. Get the logical name of the field label. For example
you can inspect the label field and find the id of that label. Screenshot attached for your reference

In my case it is cr5ce_disablitystatus_label.
Below are the steps for you.
In portal management:
1. Under content > Basic forms > Select your desired form > Additional settings
2. Scroll down until you see the javascript section
3. Then add the following jQuery
$(document).ready(function() {
console.log(555, "Ragavan Test");
$("#cr5ce_disablitystatus_label").html("Important <br><hr> This is sample test<br>Submit your application and receive a conditional offer letter with a link to book for a literacy and numeracy assessment time.<br>Book a literacy and numeracy assessment time. Please allow two hours maximum to complete both tests.");
});
You can play around with all sorts of HTML tags in the above sample jQuery area according to your need.
In portal studio:
1. Press sync configuration and browse the website
2. If not rendering properly> then Ctrl + F5 for hard refresh
Output:

Hope it helps.
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