This question isn't super clear but based on my understanding of the question, the fertilized cell divides repeatedly to form the blastocyst and later takes the form of the embryo.
Immediately after fertilization, a zygote is formed. This zygote travels through the fallopian tube undergoing multiple divisions to eventually form a ball of cells that we refer to as the blastocyst. The blastocyst is what reaches the uterine wall and implants. Once implantation occurs, a number of hormonal changes are triggered that allows the entire process of pregnancy to continue. Following the moment of implantation, the ball of cells known as a blastocyst is then referred to as an embryo. The process from zygote to implantation takes about a week on average.