"赋初值" can be translated as "initialize (a variable)" or "assign initial values" in English, depending on the context.
"Initialize (a variable)" emphasizes the act of setting a variable to its starting state or value.
"Assign initial values" more directly describes the process of giving variables their first or starting values.
For example:
"We need to initialize the variables before using them in the program."（在使用程序中的变量之前，我们需要对它们进行赋初值/初始化。）
"The algorithm assigns initial values to all parameters at the beginning."（该算法在开始时为所有参数赋初值。）