Yes, it’s absolutely safe to take two pills in one day, including taking two pills at once. That said, the most effective and best way to take your birth control pill is to take one every day (and if you’re taking the mini-pill, it’s extra important to take it at the same time every day). Regularly taking more than one pill a day won’t make your birth control more effective.
However, if you miss a pill, take it as soon as you remember, even if that means it’s at the same time as your next regularly scheduled dose. You might feel nauseated if you have to do this, especially if you need to take two pills at once, so take your pills with food.