To convert a date to the month name, you can use the Text Function. Otherwise, please check how to convert a date to the month numbers.
To convert a date to the month name with 3 letters (e.g., Aug), please copy the formula and change the cell name.
=Text(A1,"MMM")
To convert a date to the month with all letters (e.g., August), please copy the formula and change the cell name.
=Text(A1,"MMMM")
Alternatively, please follow the steps below to format the date into the month name:
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 "mmm" in the type box to have the month name with 3 letters and type "mmmm" in the box to have the full month names;
Step 4: Click "OK" at the bottom.