The task board shareable link will allow you to give your clients access to a specific task board without any access to the project and in read mode only.
Choose from the menu Tasks and Boards:
Open the task board to which you want your client to have access in read mode only.
Click on the More button and then Create shareable link:
PSOhub will open up the following dialog box where you will be able to click Copy to copy the link to this task board and send it to your client via email:
When you want to remove your client's access to the task board, simple come back here and click the button Remove guest link.