How to Add a Big Text Box

In Python Add-on I added a string attribute that can be used to fill in the contents of a string.

However, in the process of editing, if I write too much content and have to change lines, the string property box does not seem convenient.

Is it possible to create a text window that can be adjusted in height to facilitate writing multiple lines of content? Just like the Discription property of metadata when saving a component as shown in the figure below.

No. If you want to have any kind of rich UI you need to make a .NET add-on instead.