What is the Budget Checking feature? (QuickBooks Online)
The Budget Checking feature makes sure that an Organisation does not overspend, i.e. does not spend more money than intended:

Budgets are prepared in QuickBooks Online, and then
synced to ApprovalMax where Bills, Purchase Orders and Expenses get checked against the respective budgets.
Budget Checking will consider requests that have been approved before the budget got uploaded to ApprovalMax - if these requests relate to the budget (i.e. via Date/Category).