Phishing text

See the following Apple articles:

Recognize and avoid phishing messages, phony support calls, and other scams

Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support

If you think your Apple ID has been compromised

If you think your Apple ID has been compromised - Apple Support

Today-18 wrote:

I clicked a link on a phishing text & started to complete information on my iPhone but got suspicious so stopped before paying any money or pressing send, is my data under threat

Potentially, yes.

If you entered a credit card number in an input field, watch that card for (unauthorized) charges.

If you provided a password or other credentials, change the passwords now.

If you provided an email address, more spam to that email address is possible, and potentially also phishing related to whatever scheme this was.

Put differently, yes, websites can acquire text before pressing the submit button, if the website is coded to do that.