@Dhiren Naik - You have two options. The first is single-tenant per database and the second is multi-tenant per database. A single retail shop would be a single tenant. The single-tenant per database is easy to set-up and secure but complex to manage and can be very expensive. The multi-tenant per database has some complexity in setting up but is considerably more cost effective than single-tenant per database at considerable scale.
The following documentation is extremely useful in helping to make some key decisions that will guide you on an implementation strategy. Please see: Multi-tenant SaaS database tenancy patterns and there is an example solution you can set-up as a demonstration or proof-of-concept. Please see: The Wingtip Tickets SaaS application
Azure SQL Database does offer a Hyperscale service tier, which has support up to 100 TB.