why does this weird textbox appear randomly? Ive asked others and no one has experienced this?

Tap and hold with 3 fingers anywhere on the screen to bring up that shortcut bar.

Also see the "Open the shortcut bar" section of https://www.macworld.com/article/233056/ios-13-and-ipados-13-how-to-use-the-new-gestures-for-cut-copy-paste-undo-and-redo.html

It’s a copy, paste, cut menu.

https://support.apple.com/guide/iphone/cut-copy-paste-iphone-devices-iph220ea8dca/ios

• Copy: Pinch closed with three fingers.
• Cut: Pinch closed with three fingers two times.
• Paste: Pinch open with three fingers.