This is an important question, to which I will only be able to give a brief answer.
God is omniscient (all-knowing) and omnipotent (all-mighty, all-powerful). He is also infinitely loving. God created all things, and mankind specifically, out of love. His desire is to give us the greatest thing which could possibly be given by God to His creation – the opportunity to enter into a relationship of love with Him.
A relationship of love can only be entered into by the free-will choice of those involved in that relationship. God gave man free will so that he could choose to love. Giving man that free will also carries the risk that man would choose false self-love over true love; choose selfishness, choose to use people rather than to love them, choose indifference, choose hate – choose sin. A great deal of the “evil and suffering” in this world is the result of our misuse of our free will, man’s inhumanity to man.
In addition to this man made “evil and suffering”, there are also natural disasters of many types, sickness, accidents, and the ultimate reality of death which comes to all of us. It is this combination of things which I presume the questioner was referring to when they said “evil and suffering”.
I would now like to make a distinction between God’s will and God’s providence. God’s will is what He wants to have happen. God’s providence is what is under His control. Because God is omniscient and omnipotent, everything that happens is within His providence. But, because God gave us free will, our own will, He gave us the power, within the limits of our being, to do things that are not His will. So, while everything is in God’s providence, not everything is according to His will.
When man chooses to sin, God could cut him off, stop him in his tracks. Of course then man’s free will would be gone, and along with it the possibility of choosing to turn again and love God. Instead, God gives man some space; permits him to sin, permits him to see the consequences of his sin (evil and suffering), gives him the opportunity to learn, to gain the knowledge of good and evil, and the ability to choose on his own to return to the good. This is the same thing every parent does with their child, who has to grow from an infant through rebellious youth and (hopefully) to a mature choice to love the parent that has always loved them.
However, while God permits man to violate His will, He continues to keep everything within His Providence. He permits sin and its consequences, giving us both free will and the opportunity to see firsthand why we should choose love and not sin. But he holds us back from the full destruction of sin by limiting our power, limiting our opportunity. If He didn’t we would long since have destroyed ourselves completely. In addition to reining in our sin, through His providence He arranges everything so that there is always a pathway for us to return, always a possibility of repentance, a possibility to turn back from sin and toward divine love.
Perhaps the most amazing aspect of Divine providence is God’s ability to “make the evil be good by His goodness”. Things which appear to be “evil and suffering”, through the power of God’s love and our participation in that love, actually become sources of good and of love themselves.
How many times families which are estranged wake up when one member has a serious illness, realizing that their arguments are petty and insignificant, reuniting in love? How many times have economic problems made people realize that material things are not what is really valuable? How many times has a natural disaster helped people see that they have more in common than what divides them? How many times have wars helped people value peace? How many times, during a terrible trial, has someone risen up, someone we never would have guessed, faced seemingly insurmountable odds, and inspired us all with the courage behind their love? How many times have people of faith, faced with the skepticism and derision of non-believers, learned better how to understand their own faith and become closer to God? How many times have people achieved all their earthly goals and only then come to see that these are lesser, that our true goal and destiny lies in God?
Virtue becomes real only when it is tested. Love becomes stronger as it overcomes difficulties. The end of our life on this earth is the beginning of our life in heaven, just as the end of our life in the womb was the beginning of our life here.
A tiny baby only knows that the needle hurts; The nurse knows that the shot is good. The child throwing a tantrum doesn’t understand why their mother isn’t giving them what they want. God’s wisdom is infinitely greater than ours. We cannot bridge this gap to understand His wisdom. We have to trust Him; We have to have faith.
“why is there so much Evil and suffering in this world?"
So that we can choose to love. So that we can find, through it, a path toward the love of God and our fellow man. So that we can learn, truly learn, compassion, forgiveness, generosity, selflessness. So that we can truly become human – truly love.
May God grant us wisdom!