By default you might have signed up for Olvy with organisation in the the Free plan. The free plan is great to get started with, but if you want features like multiple users, custom CSS support, custom domains etc. you will have to get a Pro subscription for Olvy.
To upgrade your Olvy subscription you will need to go to your organisation's billing settings. To do that at the top of the left sidebar click on your organisation's name and in the dropdown that opens click on Billing.

On the Billing page you will the plans available, and options to choose your currency (currently we support only INR and USD, but you can make a purchase using any amount), and a billing frequency option. We recommend going for annual billing as that also gives you a small discount on your total bill for Olvy.
Managing your subscription
Once you have a paid subscription to Olvy, the billing settings page will show you details on the plan you are on, when was it bought, and till when it is valid. The page will also have a link to go to your customer portal where you can manage your payment settings or cancel your Olvy plan if you want.