Quotes are added as jobs in the system. We only tag them as Quotes in the job detail section.
The easiest way to track Quotes is using a custom job status called "Quote". Create a status ( Settings > Company Account > Job Status Management ) and add your Quote related flags such as "New Quote" (green), "Quote declined" (grey), etc.
When you add a job, make sure that you select Quote in the job status section. It will help you manage the end to end Quoting process.