32/64 bit for software/hardware has nothing to do with security.
Is kinda like how many lanes a road has.
The more lanes, the more cars can use that road at the same time.
In computer terms :
the more lanes, the more data can travel/be handled at the same time.
When it comes to security, yes it also partly about bits.
But that is entirely different.
To put it in real simple words...
A password of 32 bits (characters) is easier to guess than one with 64 bits.
If you want to learn about computers (hardware/software), I can recommend this website :
http://computer.howstuffworks.com/