A little Comic Lore for funsies,
The Scarlett Witch is an older character than you would think, She has been around for a while.
her first appearance was in the X-Men number 4, " Yes, She appeared just three issues after Magento Did."
Originally, She was Thought to be the Daughter Of Magneto, She was so certain of this, Much of her early Character arc in the '60s was to simply get magneto to confess this, It was later revealed that she and her Brother Quicksilver were the children of an old 1970's hero
The Wizzer, Wasn't anything special, He was a Marvel Clone of Dc's Flash. He was later removed from the comics entirely because of legal issues. but, This would explain, Quicksilver's speed. Would explain it, However, It was later retconned "A comics word, Meaning, The older canon of the story was changed by the revelation of a future event" SO, It was Retconned, That The now Wanda Frank, Who had changed her last name to the Family name of her Father, Was in fact, Not a Mutant, That her and her brother quicksilver Were in fact Test subjects of the High Evolutionary.
The High Evolutionary. Guess what his powers are? He literally is a mutant, His ability is the power to genetically alter any life form however he sees fit.
His goal was to create Gods. Why? Just to see if he could, This guy is that crazy powerful. So, Wanda and Quicksilver are not Mutants. They are in fact, Humans who were genetically altered By The High Evolutionary at birth to be what he thought a God should be. After this was revealed, She Changed her Last name to Maximoff, In honor of her Adopted Parents.
So, Wanda isn't really a Mutant, However, She and her brother's powers are "because of" a Mutant. And That's about all there is to know in a nutshell. There Is More, But, Who needs an encyclopedic breakdown. Ya know?