Variable or Fixed Size Frames
Each frame can either have a variable or a fixed size.
Variable size frames adapt to the text length, whereas fixed size frames always remain as they are, no matter what the text length is. So if you choose a fixed size frame and the length of your text exceeds the frame size, then the text will extend beyond the frame.
Fixed frame sizes are defined in the standards. You can have multiple fixed sized frames. You can edit and manage them in the standards. For more information, see Frame Definition and Changing Frame Sizes for Fixed Frames.