I work in insolvency and there is so much poor information on this thread, it's no wonder people end up in the wrong solutions.
@GrinchoftheNorth has it right.
An IVA is a legally binding contract between you and your creditors where you agree to pay a fixed monthly amount typically over 5 or 6 years and whatever is left over after the IVA is completed is written off.
There are fees for the IP to help you set up and administer the IVA, nowadays it's usually a fixed fee of anywhere between £3.5k and £4.5k. It comes out of your monthly contributions and you do not have to pay anything up front.
If your IVA fails early though, you will find that more of your payments will likely have paid towards the fees than your debts so you need to be as confident as you can be that you'll be able to maintain the payments for the full term.
You are expected to provide information for an annual income and expenditure review to ensure your payments remain at the right level, you have to inform your supervisor of any changes to your income such as a pay rise, redundancy or a windfall, and you can't take out credit of more than £500 without the approval of your supervisor, but otherwise on a daily basis your money is yours to do what you want with. It's not constantly monitored.
£6,000 is a pretty low amount of debt for an IVA and I wonder why the alternatives were not deemed suitable? So you own a house or expensive car? If not a DRO might be more suitable; it's free and you'd be debt free after year.
Alternatively in a DMP (be careful as there are free ones but also companies who charge extortionate fees) you'd be debt free in 5 years with a £100pm payment.
There's such a lot of information to take in when considering an IVA and i get it's probably totally overwhelming. Just don't be afraid to approach Stepchange to ask questions or to clarify anything you don't understand, or alternatively seek free independent debt advice. Have a look on the moneyhelper website (run by Money and Pensions Service which is govt funded).