Question

proper use of can and could

Answer 1

can is used for something is happening or go to happen..
while could is used for past tense..
like
akbar could defeat the hemu.

Answer 2

can is used for the permission but which is not formal .it is also use for build up the strength of any person
you can do it
can also used for description and request of some un formal aswet
could is the past tense of can
it used for above mentions and also any incident happen in past