Does Man Determine His Destiny (Qadar) On His Own?

It is said that man predetermines his own destiny, is it true?

Answer:

Destiny (qadar) refers to Allah’s (swt) knowing everything that has happened and will happen in the universe with His eternal knowledge and recording them to the Preserved Tablet (al-lawh-i mahfuz).
Destiny consists of two parts:
One part is called

“non-changeable destiny” (Izdirari Qadar)

. In this part of destiny, there is no intervention or effect of the human will. For example, biological activities in our body such as the blood circulation, cell reproduction and death or where a person will be born, his sex, who his parents will be, fall into this category. In non-changeable destiny, Allah’s abundant (absolute) will is essential. There is no effect of person’s free will.
The other part is called

“changeable destiny” (Ikhtiyari Qadar)

and in this one human

“will” (iradah)

plays its role. Man asks with his will and Allah (swt), with His absolute will and strength, bestows what the man has asked.
A person’s choice of career, environment, spouse and friends falls into this category.