An invoice or bill is a commercial document issued by a seller to the buyer, indicating the products, quantities, and agreed prices for products or services the seller has provided the buyer. An invoice indicates the buyer must pay the seller, according to the payment terms. wikipedia.org

Reconciliation is the process of ensuring that two sets of records (usually the balances of two accounts) are in agreement. wikipedia.org

QuickBooks is a line of business accounting software developed and marketed by Intuit. wikipedia.org

Microsoft Excel is a proprietary commercial spreadsheet application written and distributed by Microsoft for Microsoft Windows and Mac OS X. It features calculation, graphing tools, pivot tables, and a macro programming language called Visual Basic for Applications. wikipedia.org

A data entry clerk, sometimes called a typist, is a member of staff employed to type data into a database using a keyboard. The keyboards used can often have specialist keys and multiple colours to help them in the task and speed up the work. wikipedia.org

Customer service is the provision of service to customers before, during and after a purchase. wikipedia.org

A Bank reconciliation is a process that explains the difference between the bank balance shown in an organisation's bank statement, as supplied by the bank, and the corresponding amount shown in the organisation's own accounting records at a particular point in time. wikipedia.org

Bookkeeping is the recording of financial transactions. Transactions include sales, purchases, income, receipts and payments by an individual or organization. Bookkeeping is usually performed by a bookkeeper. wikipedia.org

Financial accountancy (or financial accounting) is the field of accountancy concerned with the preparation of financial statements for decision makers, such as stockholders, suppliers, banks, employees, government agencies, owners, and other stakeholders.

Accounts payable is a file or account sub-ledger that records amounts that a person or company owes to suppliers, but has not paid yet (a form of debt), sometimes referred as trade payables. wikipedia.org