How do I cancel text box on phone?

Force restart the iPhone. Follow the directions under "If your screen is black or frozen" here.

If your iPhone, iPad, or iPod touch won't turn on or is frozen - Apple Support

Okay, so you touch the icon for the phone, and when it opens you see a text message screen. What screen exactly? As sberman said, can you provide a screenshot of this, since it sounds strange and I cannot imagine what it looks like. You can redact any personal information from the photo, so long as it shows what you are referring to.

When you refer to the phone-call screen, are you just speaking about the home screen for the phone, where you see all of the icons? Are you seeing a Notification for a text message that is persistent on the screen? There are multiple settings for Notifications, and it would depend on how those are configured as to what is showing and what to do to get rid of it.

IF this is not what you are referring to, then I'm confused as well by your description of the problem.

Hi! Thanks for your message. I might have not explained it correctly. My partners phone-call screen has text message box showing & I want to get it off. This probably sounds really stupid. Would you know? Thanks. Happy New Year!

What is a "phone call screen"?

Is that something one sees when placing a call? When receiving a call? Would you be able to post a screen shot?

Hi, no, I meant the screen that appears when touching the phone ic

FYI, here is something resembling what I see while on a call. Compare what you see to this, if you like.

Hi! I’ll need to check in later. My partner says it is now working normally. Than

Okay, sounds good. At least it is working. Even if you cannot capture a screenshot, if you can at least capture the exact text of the error message so that can be shared helps.