In the upper left part of the "Estimate" section there is a status field (a group of circles with numbers in them). In fact, the current status of the estimate corresponds to one of the stages of the project development. The user can set the number of statuses and their names himself (more detailed information on the topic can be found in the "Global Settings" section). To the right and left of the status circles are arrows that allow you to transfer the estimate from one status to another. 

Note that in order to avoid confusion in the warehouse, the "Specification" section directly related to the warehouse (see below), if necessary, can actually be made unavailable until the estimate reaches a certain status (for example, "approved by the customer"). This bundle, if needed, can be configured by the user himself.