Create invoices the way you like them to. Add your brand logo and customise it such that your customers get a feel of your brand.
Be it weddings or birthdays, let your clients know what they would be paying for with detailed estimates. Provide appropriate discounts, mention the terms and conditions of your business, and let your clients make comments if necessary.
Don't spend your time and space on paper receipts. Whether it is wedding decors, transportation, or purchase invoices, know where exactly you are spending the most with comprehensive reports.