User wants to apply a fee schedule to an estimate, i.e., bill rates and cost rates already associated with activities to an estimate to save time.
In Core, Fee Schedules have resources (employees and vendors) and activities that are used to match bill and cost rates. On the other hand, estimates do not have resources, so there is no way to use fee schedules on them. The workaround for this is to use budgets.
Budgets have both resources and activities, which allows us to use fee schedules with them. So either you can use budgets instead of estimates or you can convert those budgets into estimates automatically by click of a button. Check the Core Help for details.