To file a dispute with Experian credit bureau you must write a dispute letter. When they receive your dispute letter they will investigate the disputed listing.
However the first step is to request a copy of your credit report. This can be done for free from annual credit report. It is your right to have a free copy of your credit report from each credit bureau once a year.
Often your credit report will be made available online; you need to then decide what items are inaccurate or incorrect. These are going to be the items you dispute.
These marks are disputed by writing a dispute letter and sending it to Experian. Upon receipt they will say if your dispute is valid or invalid.
If it is found to be invalid then they will write you requesting more information about the dispute. If this happens you will need to respond accordingly and provide the requested details.
However if they find your dispute valid they will investigate the mark. During an investigation they will contact the originator of the item and ask them to verify the account, the balance, and the dates on the account.
It has been found that investigations will often result in a listing being removed. This is a result of many businesses being unwilling to spend the resources verifying disputed debts.
Your other option to dispute bad credit is to hire a credit repair service. If you do hire a service all you will need to do is identify what items you wish to dispute.
The benefit of a service is they can use advanced dispute techniques such as; debt validation, escalated dispute information requests, and creditor direct intervention.
If you have multiple bad credit items you wish to dispute then I suggest hiring a service, in addition they will have no problem getting a valid dispute submitted. However if you only have one or two bad credit items to dispute then you can do it yourself.
Be aware that you must send a dispute letter to each credit bureau. If you do not you may remove a negative mark from your Experian credit report however this mark will still be on your Equifax and Transunion credit report.
In sum negative items can be removed from your credit report. You do not have to live with the high cost of low credit.