In which mitotic phase do the chromosomes condense and does the mitotic spindle begin to form?

The chromosomes condense and the mitotic spindle begin to form in the Prophase.

Explanation:

Mitosis is a phenomenon in which a parent cell copies itself to form identical, two new daughter cells. Generally, the process of mitosis can be divided into 5 phases:

Interphase

Prophase

Metaphase

Anaphase

Telophase

The process of cell division starts from the prophase. In this phase, the duplicated parent cells condense. The mitotic spindle, which functions to separate the sister chromatids, also forms during the prophase of the mitotic cycle.