Hi GAIL - I'll need some more info to answer your query specifically, however as a guide:
There are two types of loan - Secured and Un-Secured. The first uses the equity (Value of your home minus outstanding debt) as collateral to secure the finance you borrow. The main advantages are you can borrow over a longer peiod of time (can be upto 25years) helping to bring monthly repayments down. Other plus's are that because the loan is Secured against your property the lender is more likely to accept you than for an un-secured loan.
The downside to a Secured Loan is it's Secured against your property. You must manage your loan responsibly as your home could be put at risk if you don't meet repayments.
Un-secured loans are for amounts up to £25,000. And lending is based on your personal circumstances (i.e. credit history and ability to repay the loan) and not in any way tied to your home.
In regard to having a co-signiature. The Secured Loan will need to have approval and signiature of anyone on the deeds for the property. If you're not a homeowner it's simply not an option.
Un-secured will be based on your personal circumstances. So as long as you apply in your name alone you shouldn't need one. Some people use a co-signiatory as guarantor when they know there credit history prevents them from getting the loan they want.
Apologies if i've not answered your question but it's difficult without understanding more about what you're specifacally looking to understand?
Think about what you're after the loan for. If it's a small advance (say less than £5K) and you want to repay quickly then uin-secured is a better option. Do lots of research and use the loan comparison tools on this site to find a product that's right for you.
Get in touch again if you need any help.
moneysupermarket.com loans team.