From the WordPress dashboard click on 6storage -> Settings.
After selecting the Settings you will land on the Tenant Portal Settings page.
To customize this display click on Feature Customization. There, you will find Fields, Additional addons & other operations.
By disabling the reservation option, the reservation button will not be available on the tenant portal.
As you can see, the reservation button is not available.
By enabling the reservation option, the reservation button will be available in the tenant portal.
As you can see in the below image the reservation button is enabled