CRM is “customer relationship management” i.e. a system to manage interactions with customers such as tracking calls, marketing emails and collateral, meetings, quoting, support tickets, and more. It tracks the lifecycle/pipeline of a sale from prospecting, lead qualification and solution mapping, demos and meetings, proposals, negotiations and commitment, opportunity win/loss, license generation, onboarding, renewals, and a ridiculously huge number of other things.
It’s not just tracking the numbers but giving you a centralised system that all other business operations can hook into so you’ve a single source of truth about customer state so that various other operations can be triggered.
When you’ve hundreds of sales people, numerous systems, marketing people, support teams, and more all reading and writing to the same CRM system, if that “system” was a spreadsheet, you’d be constantly deadlocking and race conditioning the hell out of it, not to mention how absurdly huge that file would become with all that historical data (since a big part of CRM is also projections and other analyses across all the data you have).
Honestly, it’s very likely just Salesforce since that cantankerous, janky beast is so easy to use poorly.