In Confluence, while in Edit Mode, you have the option to use the Date picker (//) in order to display a Calendar and select a day to insert in the page.

However, it will only display the day and the year, not pointing which weekday would be. For example, the following screenshots:

To display the Calendar with the days:

Then, once you have selected the day, here's what it looks like:

This is an improvement request to also display the weekday, once the date is inserted.