What is the difference between a credit card and a pre approved credit card or is there no difference?

I am looking to raise my credit score and I have been turned down buy credit card companies and I spoke with someone that said I could get a pre approved credit card but i thought all credit cards were pre approved. Please help me I need to raise my credit score. Thanks

How do I get on credit card mailing lists, to receive credit card offers?

My friend gets over 75 pre-approved credit card offers a month. How do I do the same?

How do I remove myself from pre-approved Credit card offers?

I have heard that I can remove myself from pre-approved credit card offers. Does anyone know a phone number or website where I can do this at?