By default, on the Portal header, there is a lock icon, just press it:
![](https://portals-app.help/wp-content/uploads/2023/03/image-5.png)
If you have hidden that from the settings, you can find it in the menu:
![](https://portals-app.help/wp-content/uploads/2023/04/image-5.png)
If you have hidden that also, then you can also lock it form the Home page of the settings window (click the taskbar icon to open it):
![](https://portals-app.help/wp-content/uploads/2023/04/image-6.png)