Time and effort
Time is of essence for most people, and it takes time to “dot the i’s and cross the t’s”.
When you manually create an invoice (not using invoicing software), you first have to find a template that’s compliant with invoicing requirements in your country. Knowing what details to include is important for HMRC and tax returns, and you can’t always rely on templates found online from global websites.
This is then downloaded to your chosen word processor or spreadsheet program on a computer. From here on, you need to manually edit the invoice, add up the numbers and taxes, adjust formatting, etc. Invoice numbers have to be unique and chronological for each invoice, so this has to be edited every time you send a new invoice.
With invoice software, there already is a template that prompts you to input all the information required by your local tax authority (in most cases). Sometimes, you can change certain aspects of the invoice design or choose another template that suits your style better.
The software will basically ask you to add essential information like products/services sold, cost per item, business and recipient details. It also adds up the numbers and taxes for you and generates the invoice number automatically.
Some solutions let you create and manage invoices in a mobile app, not just your computer. This is usually faster and much more accessible for people on the go.