> ## Documentation Index > Fetch the complete documentation index at: https://docs.gasos.ng/llms.txt > Use this file to discover all available pages before exploring further. # Invoices and payments > Invoice a customer's fill-ups, take full or part payments, correct with credit notes, send reminders, and see who owes and how late. ## Invoices On a customer's page, choose **New invoice** and pick the period, usually **Last month**. Gasos makes a **draft** with every fill-up in the period that isn't on an invoice yet: date, station, plate, fuel, litres, price and amount (gas in kg or cylinders exchanged). A draft isn't owed and has no number yet. On the draft you can change the period, the invoice date, add **their reference** (for example their purchase order number) and a note, and add **other items**: a delivery charge, or a discount with a minus price. Choose **Save draft**, then **Issue invoice**. Issuing gives it the next number (INV-0001, INV-0002…) and a due date: the invoice date plus the customer's **Pay within** days. At the end of the month, choose **Invoice last month** on the **Invoices** page. Gasos makes a draft for every customer with fill-ups not yet invoiced; check them, then **Issue** them all at once. If an issued invoice is wrong, use a **credit note** (below) for a small correction, or **Void** it. Voiding puts its fill-ups back to not invoiced so you can invoice them again; anything paid on it becomes the customer's credit. The number isn't reused. ## Payments Choose **Record payment** on a customer or an invoice: the amount, the date received, how (bank transfer, cheque, POS or cash) and the reference. Gasos applies it to the oldest unpaid invoices first. To decide yourself, turn on **Choose which invoices it pays** and set an amount per invoice; part payments are fine, and the invoice shows **Part-paid** with what's left. Money that isn't applied, because they paid ahead or paid more, is the customer's **credit**. It's used on their next invoice when it's issued, or straight away with **Apply credit** on an unpaid invoice. **Take off** moves a payment off an invoice back to credit. ## Credit notes A credit note (CN-0001…) takes money off what a customer owes: an overcharge, a wrong price, a goodwill discount. From an invoice, choose **Credit note**, the amount and the reason; it's taken off that invoice. From the customer's page it becomes credit for their next invoice. Credit notes show on statements, and can be voided. ## Sending and reminders On an invoice, choose **Email**, **WhatsApp** (opens a chat with the link ready) or **Copy link**. The customer opens it without an account, and can print it or **Download PDF**. The invoice shows when it was sent and when they opened it, and its **Activity** keeps the whole story. Gasos reminds customers about unpaid invoices by email on the days you choose under **Credit settings** (by default 3 days before the due date, on the day, and 7, 14 and 30 days late), never more than once a day. Turn **Automatic payment reminders** off on a customer to leave them out. You can also send one by hand with **Send reminder**. ## Credit settings **Credit settings** is under **Company** in the sidebar. Because it holds the bank account customers pay into, only owners and admins can open it, or someone whose role has **Change credit settings** (see People › Roles). There they set: the invoice number prefix and next number, **Pay within** for new customers, **VAT on fuel** (none, or 7.5% included in prices), **VAT on gas (LPG)** where a station sells gas (none by default, as LPG is VAT-exempt; see [Dealers on account](/gas/dealers-on-account)), the bank details printed on invoices, a footer note, the reminder days, receipts by email for each payment, and **Invoice everyone on the 1st** to issue and email last month's invoices by itself. ## Statements Under **Statement**, choose the dates and **View statement**. It shows the opening balance, every fill-up, extra item, payment and credit note with a running balance, and what they owe at the end, across all stations. ## Who owes **Who owes** shows each customer's unpaid invoices by how late they are: not due, 1–30, 31–60, 61–90 and over 90 days past the due date. Fill-ups not invoiced yet are shown apart, and credit is taken off. Chase the oldest first, and put an account **On hold** while it's well overdue. ## Changing the bank account The bank account on your invoices is where customers send money, so changing it takes two people: * **An owner's change** applies straight away. * **Anyone else's change** waits. It shows at the top of **Payment details** until someone else who can change credit settings, or an owner, chooses **Approve change** or **Reject**. You can't approve your own change, and it expires after 7 days. Until it's approved, invoices keep the old account. Owners, and everyone who can change credit settings, are emailed about every bank account change, so nobody can change it quietly. You can't turn these emails off. Only an owner can turn off **Require a second person for bank account changes** (under **Bank account safety**). Every change, request and decision appears in the [activity log](/account/activity-log). 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