Do it take any time for the newly created field to reflect in the object once the process to create fields is initiated?

No, it doesn’t take any time. The process is instant and your field will be reflected at the same time.

Experience it for yourself

Bulk Object Field Creator (BOFC) is a must-have tool, designed specifically for Administrators, that simplifies many of the tedious tasks of managing a complex Salesforce environment.

This tool is available on Appexchange and Click on below button to install the
latest version of BOFC

or learn more