Hagar (Hebrew: הָגָר, Hāḡār; Arabic: هاجر, Hagar; "Stranger") was an Egyptian-born handmaiden of Sarah, common-law wife (i.e. concubine) of Abraham and mother of Ishmael. Her history is narrated in the Book of Genesis in the Bible.
Hagar joins Abraham
Hagar joined the camp of Abraham in the fall of 2084 AM. Abraham had come to Egypt to escape the effects of a famine in Canaan. When the Pharaoh asked Abraham to leave, Hagar left Egypt with him as a servant for Sarah.
Sarah despaired of having a child of her own. So she persuaded Abraham to father a child on Hagar. That child was Ishmael (born about January 1910 BC).
When Ishmael was fourteen years old, Isaac was born to Abraham and Sarah. Five years later, Abraham held the feast of weaning for Isaac. During this event, Ishmael mocked Isaac. For this, Sarah demanded that Abraham send Hagar and Ishmael away.
The two exiles had between them a loaf of bread and a bottle of water. In the then wilderness region of Beersheba, the water gave out. Hagar placed Ishmael a bowshot away from her, because she did not want to watch him die. But the pre-incarnate Jesus Christ visited her, assured her that they would both live, and even provided water from a miraculous well.
Thus they crossed the desert. The Bible says nothing further about the life of Hagar.