Yes — for many trades it's a sensible choice. Invoice2go is a long-running invoicing app for small businesses, available on iOS, Android and the web, with estimates, receipts and in-app card payment acceptance. That cross-platform reach matters if your team uses a mix of iPhones and Android phones, or you like to finish paperwork on a computer.
The trade-offs for a UK sole trader are price and platform. Invoice2go plans run from about £9 to £25 a month at the time of writing, and the cheaper tiers are more limited. AllSquare only runs on iPhone and iPad, but Pro costs £5.99 a month (or £49.99 a year) and the free tier gives you 2 invoices and 2 estimates every month — enough for someone billing a couple of side jobs.
Day to day, the biggest difference is how an invoice gets written. In AllSquare you can fill in the form, tap items from your saved price list, or describe the job by voice or text and let the AI draft it for you to check. The manual form is always there, so the AI is a shortcut rather than a requirement.