The right app won't make or break a start-up, of course, but it can make the lives of the people behind those businesses a lot easier.

Entrepreneurs, by and large, live fast-paced, chaotic lives, where decisions have to be made quickly and inspiration can come in the most unlikely of places. They live and die by their smartphones and tablets, so it helps to have those equipped with apps that can make the most of every minute, in turn helping their businesses grow.

Here are 10 apps many entrepreneurs swear by. The best part: Most are free.

—By Chris Morris, Special to CNBC.com
Posted 12 May 2014

You never know when you're going to need to access a photo, document or video. Dropbox's cloud storage is one of the most popular around, and this Android and iOS app adds mobility to its many features. Best of all, if you lose your phone, all of your files are still safe, assuming you've synced the device to your account.

Another key cloud-based app, Evernote lets you sync notes between your phone, tablet, desktop and most other devices; edit; share files as necessary; and always be up to date with the latest version. The app, which is available for iOS and Android, also lets you save audio notes and quickly scan things, like business cards.

And for compulsive online readers who may not have time to read the stories they find, there's an in-app browser, letting you bookmark and save clips for later.

You're not always in the office when a conference call takes place, and looking up the dial-in number, the access code and so forth is a pain, especially if you're in the car. MobileDay, available for iOS and Android, simplifies that, scanning your calendar and importing all conferencing information.

When it's time for the call, you can join with just one click. And if you need to arrange a group discussion yourself, just tell the app who to invite and it will send the details for you—even setting up the call via its own conference service.

Square's peripheral payment system has revolutionized how many small businesses handle cash flow. Any mobile device—iOS or Android—can be a credit card terminal now, emailing receipts to clients and expediting the payment process. The app/card reader (which is also free but must be ordered separately) accepts all major credit cards and charges a 2.75 percent processing fee per swipe. Funds are available to the business within one or two days.

The email inbox of any entrepreneur is a scary place, regularly filling up at an astonishing rate. CloudMagic (available for both iOS and Android) stands apart from other mail apps due to its thorough search functionality, which scours all of the mail you've ever received, something Apple and Google have yet to master.

It supports multiple accounts (including Microsoft's Exchange) and scans messages, suggesting specific content (i.e. an article someone suggested) be saved to other apps, like Evernote.

Cash flow is critical for a start-up, and that means assembling and sending prompt and thorough invoices when work is done. Invoice2Go simplifies the process. From your iOS or Android phone (or desktop PC), you can quickly format and send an invoice—or, for that matter, an estimate.

The service calculates all taxes and totals and is integrated with PayPal, which could ease payments for some companies. It also automatically configures itself for clients in other countries.

Good entrepreneurs know that delegating tasks is the best way to ensure they're completed in a timely fashion. Producteev, available for iOS and Android, helps you keep track of all ongoing tasks, adding due dates and milestones and tracking progress along the way. It also offers top-quality filtering so you can see exactly how much an employee already has on their plate.

This centralized communications hub for teams is a company-specific amalgamation of Skype, Instant Messenger and email. Flowdock helps teams stay focused and on track—and offers a history of the conversation for those who are out of the loop for a while. It's one of the best ways to stay in touch and on track when a project deadline is approaching.

Web and mobile start-ups live and die on metrics. And generally, they keep watch on several different tracking sites. Pocket Analytics (an iOS exclusive) pools data from several of the Web's largest analysis sites, letting you customize your dashboard to keep track. Among the data sources are App Annie, Clicky, Facebook Insights, Flurry, Google Analytics and Pingdom.

Bosses never get real time off. There's always something that needs to be approved or signed. HelloSign, though, lets you review and sign documents without having to visit the office. There's no printing, signing and scanning with this iOS and Android app. Just use your fingertip to sign any PDF file, which can then be forwarded to the necessary parties. It's a fast way to handle contracts, NDAs or other agreements.