If you want part of your page to stay static, and part of your page to scroll, you could use one Column to contain the static portion of your app screen, and one scrollable Column to contain the scrollable part of your screen.
If you want your Text Input to show its text over multiple lines, you can enable the Multiline property and set TextBreakStrategy to Simple. You can find these settings in the Advanced tab of the properties panel on the right hand side of the screen.
You can view a project with a Text Input with these properties here. You can hit the enter key to create a line break. If you type a lot of text onto one line, you will see that a line break is automatically added.