From Sales open the Quotes tab and press New quote. Pick the customer and items as on an invoice, and set Valid until. The Terms box fills in from what you wrote in Settings under Quote terms.
A quote is not an accounting document: it posts no journal, moves no stock, and is not a debt on the customer.
2
Number it, then send it
Press Save draft if it is not ready. When it is, press Save & send: it takes a number and its status becomes Sent. That button only records the status and delivers nothing to the customer. To actually send it, use Email or Send on WhatsApp on the quote page, or copy the Customer link.
3
Record the answer
On the quote page, in the Quote status card, choose Accepted or Rejected. The status lets you filter the list and see which quotes are still open.
Draft
Sent
Accepted
Invoiced
4
Convert it
Press Convert to invoice (1): a draft invoice opens with the same customer, lines and terms, dated today. Check it and issue it, and the quote becomes Invoiced.
If the goods will be held and delivered later, press Convert to sales order (2).
A rejected quote cannot be converted. For a similar quote, press Duplicate to get a new draft.