All + everybody/everyone:
We do not normally use 'all' to mean 'everyone/everybody'.
Example:
Everybody enjoyed the party (all enjoyed the party = wrong)
But we can say 'all of us'.
Example:
All of us enjoyed the party.
All + everything:
You can say 'all I can' or 'all I need'. You can also say 'all about'. This instead of 'everything'.
Examples:
I'll do all I can to help.
I'll do everything I can to help.
We can use 'all' to mean the only thing(s).
Examples:
All I've done is ride my bike (I haven't done anything else).