Dates in Excel are stored as serial numbers which can be switched from one format to another. There are many different ways to display a date.
To convert a date into "YYYYMMDD" format, please copy the formula below and change A2 in your file.
=Text(A2,"YYYYMMDD")
Alternatively, you can format the dates to the YYYYMMDD format with the steps below:
Step 1: Select the date range and click the "Home" tab from the ribbon;
Step 2: Click the right bottom corner in the "Number" group;
Step 3: In the "Format Cell" window, click "Custom" and type "YYYYMMDD" in the type box;
Step 4: Click "OK".