If you're targeting more than one operating system, these high-level pointers will get you in the door and keep you on track.

If making a budget seems daunting, you're not alone. That's why many apps do the grunt work for you. A good budgeting app can save you time and energy while helping you to spend smarter and save more.

But of course, not every business likes emojis alongside their invoices, and that's where apps like PayPal — which has a slightly more sophisticated invoicing set-up — come in. Factors like ...