Hello,
The arrow is typically used to indicate the direction of data flow. You can add arrow by adding an input port and connecting the port with the left bottom input of the subsystem, that will create an arrow. To encapsulate a mask in Simulink, you can follow these steps:
- Select the block that you want to encapsulate with a mask.
- Right-click on the block and choose "Mask" > "Create Mask" from the context menu.
- A "Create Mask" dialog box will appear. Here, you can define the mask parameters and customize the appearance of the mask.
- Specify the mask parameters by adding dialog controls, such as edit fields, checkboxes, or drop-down menus, to the mask dialog box.
- Customize the appearance of the mask using graphical elements like text, lines, or images.
Hope this helps!

