Unless you have created a Sole Proprietorship entity, having a business banking account is an absolute must. If a company is combining business and personal accounts, the corporate liability protection could be lost. This will open the door to creditors, including the IRS, pursuing the personal assets of the business owner.
To create a business account, the following will be required: your EIN / Tax ID Number; and, depending on the entity type that was created, possibly a business license, partnership agreement, or articles of incorporation.
There are many types of business checking and savings account available. You should do some research to find one that best fits your requirements. Free or no fee business checking accounts are available at most major and local banks.
A business only operating account is essential for keeping your business expenses in one location. Running all purchases and payments through one account will make doing the business accounting significantly easier. It will also contain a record of all expenses in the case of an audit.
If you are going to be setting up payroll for employees, you may also want to consider opening a second checking account specifically for your payroll. Separating payroll out of your operating account will make your accounting and taxes significantly easier.