When business software serves dozens or hundreds of different companies at once, the most important question is not "how many features does it have" but "how does it guarantee my data stays mine". The technical answer to that is a multi-tenant architecture.
What it means in practice
In a multi-tenant system, each company (tenant) has its data logically separated from everyone else's, while sharing the same technical infrastructure. Every database query, every quote, every customer is always filtered by the identity of the company making the request — no data should ever be visible to a company other than the one that created it.
Where the risk can hide
The risk in a multi-tenant system almost never lies in the visible interface, but in the code that queries the database: a query written without the correct company filter can, in theory, return another company's data. That is why the most robust systems apply the isolation check at more than one level, not only in the application but in the database itself.
Why it is worth asking outright
Before entrusting your commercial data — margins, customers, the prices you charge — to shared software, it is entirely reasonable to ask how isolation between companies is guaranteed. A serious supplier has a clear and verifiable answer, not just a general reassurance.