Create contact records when you deal with the same customers or suppliers on a regular basis. This saves you time when entering your income and expenses and helps you keep track of who owes you money and who you owe money to.
When you start entering transactions such as sales invoices, we use the information set on the contact record to determine the ledger account, VAT rate, due date, currency and price.
You can create contact records with as little information as just a Name.
NOTE: You can come back at any time to add or update their contact details. Once you've created the contact, selecting it during invoice creation automatically links it to that contact. For more detailed information on creating a contact take a look at Create a customer contact and Create a supplier contact articles.
If you already have a list of existing customers or suppliers, consider importing them from a spreadsheet (CSV file). take a look at Import, export and update customers and suppliers article on how to import your contacts.