chem redox :( help plz~

When can a reaction occurs actually?
When one compound is ready to gain and one compound is ready to lose electrons.

It is obvious when metal Aand metal B solution reacts, if metal A is more reactive than metal B, then the result is metal B + metal A solution
BUT when it is not just about metals, how then?
e.g. WHY CH3COOH + KOH has reaction?
The above example is an acid-base reaction. It is definded as it because it is a special case of redox reaction(e- are transfered from OH- to H+)

WHY doesn't Cu + 2H+ has reaction ???
Cu is more likely to gain electrons than H. So H+ cannot gain electrons from Cu. It can be known from the ECS

HOW do I know it is a strong RA or OA?
Just Check the ECS

HCl is covalent or ionic bond ar?
Covalent in gas, but dissociated in aqueous solution.

And also when do an acid uses its acid property and when its oxidizing property? what is the difference? why is there a difference?
See if the anion is stable when it is concentrate. If the anion is more likely to gain electrons than H+, it will show its oxidizing property.

"When one compound is ready to gain and one compound is ready to lose electrons"
how about neutralization? electron transfer is not involved.