D365BC is available on twio main platforms:
- SaaS: all the infrastructure is managed by Microsoft. You don't pay for hardware or resources, just a fee for the users (and ax extra fee for db space if you overcome the 80Gb limit).
- On-Premise: you're responsible for managing the database and the hardware for implementing D365BC. Here you have other choices like:
- deploy D365BC on a full on-premise infrastructure (you host the DB and the service tier)
- deploy D365BC on a PaaS cloud: you can create Azure VMs for handling your servers or also you can create the database in the cloud (with Azure SQL)
With an on-premise scenario, you can modify also the standard Microsoft's base application (not recommended, but possible), on a SaaS environment you cannot modify standard code but only subscrive to events raised by the standard. On both environments you can create your own customizations or implementations of new features.
For system requirements for on-premise, check here:
docs.microsoft.com/.../system-requirement-business-central-v16
