An IRS audit is a process by which the IRS checks the tax information you've reported to make sure everything is accurate. To prepare for an IRS audit you must first go over all correspondence that you have received. You can visit highburytaxsolutions to know more about tax audit.
There is a good chance that you will receive a notice of a tax audit requesting particular documentation. All you have to do is remit this information and let the IRS take things from there. As long as you have what you need you should not run into any issues in this area.
What about hiring a professional tax firm? It costs money to hire a professional, but they will be there to help you from start to finish so, in the end, it is well worth it. They can even talk directly to the IRS for you if you give them permission to do so. When you hire a professional you are taking a lot of the stress.
Do not be scared! It is easy to be stressed and scared if you are being audited by the IRS. But remember, there is no reason for this and if you find a good professional there is even less to worry about. An IRS audit does not mean that you are in the wrong. It just means that the IRS has decided to double check your work and cross references it with your records.