As parent, I am new to this question. What really is the differences between SAT and ACT test? Is this depends on which region of college/Univ. your kid is planning to apply? Will most (or all) of the college/Univ. accept either one of them? My kid took ACT already. Does she need to take SAT too? I heard one of these two types of test will report "ALL" test scores to the school you want to apply if you take more than one time of that test. Is it true? Please advise.

It can depend on what the college they want to attend require. So have you contated the colleges they may wish to apply to and ask them what requirements are ?

A lot of schools on the west coast usually take ACT scores. In most other places colleges look mainly at the SAT, but also consider ACT scores. All of the colleges I applied to last year took only SAT scores, but it really depends on the schools your child is applying to. If you check the schools' websites you can easily find out which tests are required.